@inproceedings{DoetschHolthausTrifonovetal., author = {D{\"o}tsch, Horst and Holthaus, Carsten and Trifonov, A. and Klank, Michael and Hagedorn, Oliver and Shamonin (Chamonine), Mikhail and Sch{\"u}tzmann, J.}, title = {Application of Magnetic Garnet Films for Magnetooptical Imaging of Magnetic Field Distributions}, series = {MRS Online Proceedings Library}, booktitle = {MRS Online Proceedings Library}, publisher = {Springer}, doi = {10.1557/PROC-834-J6.1}, pages = {18 -- 29}, abstract = {Rare-earth iron garnet films of high quality can be grown by liquid phase epitaxy on paramagnetic substrates of gadolinium galliumgarnet. Such films are currently used for imaging of the spatial distribution of magnetic fields. This application is based on the Faraday rotation which can strongly be enhanced by bismuth incorporation. The physical properties of the films can be controlled by the chemical composition, the growth conditions and the crystallographic orientation. The sensor properties like sensitivity, dynamic range, signal linearity and unambiguity must be optimized according to the application desired. These properties, however, are not independent of each other. In addition, they strongly depend on the optical wavelength. Thus, it is necessary to find compromises. The influence of Faraday rotation, Faraday ellipticity, optical absorption, magnetic anisotropies and film thickness on the performance of a magnetooptical indicator film is investigated. Based on the swing of the photoresponse, a new optimization process is introduced. The process is experimentally verified and application examples are demonstrated. Furthermore, two methods are presented to enhance the sensitivity of magnetooptical sensors. Using specific crystallographic orientations, an easy plane of magnetization can be induced which is inclined with respect to the film plane. If the magnetization lies in this plane a very high sensitivity is achieved. The dependence of the geometrical orientation of the easy plane on the growth direction is calculated and the sensitivity and dynamic range are derived. Experimental results of a [112] oriented garnet film are in good agreement with calculations. Garnet films which are magnetized along the film normal due to a strong induced uniaxial anisotropy support magnetic domains. If the collapse field perpendicular to the film plane is small, such films can be used as very sensitive indicator films. Such films are easier to prepare than sensitive in-plane films. However, the spatial resolution is limited by the size of the domains. This disadvantage can be avoided by applying a bias field in the film plane. Directly at the in-plane collapse field the sensor film is in-plane magnetized yielding high spatial resolution at still high sensitivity. The variation of magnetooptical images with in-plane induction is demonstrated. Experimental results are in agreement with calculations.}, language = {en} } @inproceedings{LangerHausladenPrommesbergeretal., author = {Langer, Christoph and Hausladen, Matthias and Prommesberger, Christian and Ławrowski, Robert Damian and Bachmann, Michael and D{\"u}sberg, Felix and Pahlke, Andreas and Shamonin (Chamonine), Mikhail and Schreiner, Rupert}, title = {Field emission current investigation of p-type and metallized silicon emitters in the frequency domain}, series = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, booktitle = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, publisher = {IEEE}, doi = {10.1109/IVNC.2018.8520127}, pages = {1-2}, abstract = {We investigated two different field emitter arrays consisting of 10×10 p-type and 10×10 undoped Au-coated high aspect ratio silicon tips. The I-V characterization of the p-type sample showed a pronounced saturation for voltages higher than 500 V and a maximum emission current of 39 nA. The metallized sample revealed a FN-like emission up to several μA. The metallized and the p-type sample operating below the saturation region showed high current fluctuations of ±16\%. Whereas, the metallized sample with current regulation and the p-type sample in the saturation yielded a current stability of ±0.4\% and ±0.3\%, respectively. Investigations in the frequency domain revealed the for field emission typical 1/f-noise. By operating in the saturation region (p-type sample) or using an emission current regulation (metallized sample) the noise level was reduced by at least 20 dB. Finally, the p-type sample was illuminated by a light emitting diode to increase and modulate the emission current in the saturation region. The emission current was increased by a factor of 3.7 to 145 nA. With this configuration we emulated an unstable emission behavior and evaluated the performance of our emission current regulation circuit.}, language = {en} } @article{LohmeyerShamoninChamonineHertel, author = {Lohmeyer, Manfred and Shamonin (Chamonine), Mikhail and Hertel, Peter}, title = {Boundary conditions for the finite difference beam propagation method based on plane wave solutions of the Fresnel equation}, series = {IEEE Journal of Quantum Electronics}, volume = {33}, journal = {IEEE Journal of Quantum Electronics}, number = {2}, issn = {0018-9197}, doi = {10.1109/3.552269}, pages = {279 -- 286}, abstract = {Each particular implementation of the beam propagation method (BPM) requires a special procedure allowing for radiation to leave the computational window. We propose a new approach to constructing the finite difference schemes of the BPM at the boundary of the computational window. These schemes are independent of the computed fields and allow for a similar treatment of both interior and boundary points. The new approach can be further improved by correcting the field values at the boundary points according to Hadley's method. The algorithm is easy to implement for both two- and three-dimensional structures. The new method considerably reduces computation times because the propagation matrices remain constant in longitudinally invariant sections, thus avoiding repeated LU-decompositions. The basic idea-establishing the finite difference scheme such that locally exact, approximate, or plausible solutions are recovered-may be of interest for other efforts to solve partial differential equations by the finite difference method.}, language = {en} } @article{ShamoninChamonineLohmeyerHertel, author = {Shamonin (Chamonine), Mikhail and Lohmeyer, Manfred and Hertel, Peter}, title = {Analysis of power-dependent switching between radiatively coupled planar waveguides}, series = {Journal of Lightwave Technology}, volume = {15}, journal = {Journal of Lightwave Technology}, number = {6}, publisher = {IEEE}, address = {New York}, doi = {10.1109/50.588671}, pages = {983 -- 989}, abstract = {Effective coupling between two remote optical waveguides without branching sections can be achieved in a three-guide system with multimode central waveguide. We investigate the nonlinear power switching of c.w. laser radiation by such radiatively coupled waveguides. It is shown that effective all-optical switches with spatially well separated input/output channels can be realized although the influence of multimode interference on the switching characteristics becomes more pronounced for increasing thickness of the central guide. Different coupling regimes are specified, and the changes in switching characteristics during the transformation from one regime to another is studied. Numerical calculations for the critical power are compared with an approximate analytical expression. It is also shown that, at a moderate input power, a small number of modes determines the switching behavior.}, language = {en} } @article{LohmeyerShamoninChamonineBahlmannetal., author = {Lohmeyer, Manfred and Shamonin (Chamonine), Mikhail and Bahlmann, N. and Hertel, Peter and Dotsch, H.}, title = {Radiatively Coupled Waveguide Concept for an Integrated Magneto-Optic Circulator}, series = {MRS Online Proceedings Library}, journal = {MRS Online Proceedings Library}, number = {517}, issn = {1946-4274}, doi = {10.1557/PROC-517-519}, pages = {519 -- 524}, abstract = {Three-guide couplers with multimode central waveguides allow for remote coupling between optical channels. A simple three mode approximation turns out to be sufficient for the description of the main features of the power transfer behavior. The specific form of the relevant modes suggests the design of integrated optical isolators and circulators based on magnetic garnet materials. These novel devices are superior to conventional nonreciprocal couplers with respect to the total length and admissible fabrication tolerances. We characterize the isolation performance and the transmission loss for the proposed devices by propagating mode simulations and estimate the influence of geometry parameter deviations.}, language = {en} } @masterthesis{Marterer, type = {Bachelor Thesis}, author = {Marterer, Verena}, title = {Simulation der elektromagnetischen Eigenschaften von gestricktem Stoff}, address = {Regensburg}, doi = {10.35096/othr/pub-5760}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-57605}, school = {Ostbayerische Technische Hochschule Regensburg}, abstract = {Periodische Strukturen besitzen eine Reihe interessanter Eigenschaften, die sie unter anderem f{\"u}r den Einsatz im Bereich der Hochfrequenz- und Mikrowellentechnik attraktiv erscheinen lassen. In der vorliegenden Arbeit steht insbesondere deren Anwendung beim Entwurf gestrickter Stoffe, die auf metallischen F{\"a}den basieren, im Vordergrund. Es wird in diesem Zusammenhang zun{\"a}chst die vollst{\"a}ndige Modellierung der Struktur unter Verwendung von 3D-Elementen in repr{\"a}sentativen Elementarzellen durchgef{\"u}hrt. Innerhalb der Designumgebung von CST Studio Suite kann das analytische Elementarmodell von Leaf und Glaskin f{\"u}r die Einfaden-Maschenware implementiert werden. Abh{\"a}ngig von den variablen Faktoren beim Stricken bewegen sich die Kantenl{\"a}ngen der hier betrachteten Einheitszelle in der Gr{\"o}ßenordnung von 1 cm bis 2 cm. Bei der Analyse der elektromagnetischen Eigenschaften unter Verwendung eines Frequenzbereichsl{\"o}sers k{\"o}nnen somit die Streuparameter f{\"u}r Reflexion und Transmission in einem Frequenzbereich von 13 GHz bis 30 GHz ermittelt werden. Aus den 1D-Simulationsergebnissen werden Frequenzen sichtbar, bei denen Resonanzph{\"a}nomene auftreten. Die polarisationsabh{\"a}ngigen Strukturen weisen Abschirmwirkungen von 30 dB und mehr auf. Da das Resonanzverhalten mit den Oberfl{\"a}chenstr{\"o}men in Verbindung steht, wird die Oberfl{\"a}chenstromverteilung zeitgleich mit dem elektrischen Feld untersucht. Weiterhin wird den Wechselwirkungen zwischen den ver{\"a}nderlichen Strickparametern und den elektromagnetischen Spezifikationen wie Resonanzfrequenz, Bandbreite oder G{\"u}te Aufmerksamkeit geschenkt. Es wird deutlich, dass Optimierungsroutinen die M{\"o}glichkeit nahelegen, frequenzselektive gestrickte Strukturen f{\"u}r diverse Anwendungen maßzuschneidern.}, language = {de} } @article{ShamoninChamonineLohmeyerHertel, author = {Shamonin (Chamonine), Mikhail and Lohmeyer, Manfred and Hertel, Peter}, title = {Directional coupler based on radiatively coupled waveguides}, series = {Applied optics (Appl. Opt.)}, volume = {36}, journal = {Applied optics (Appl. Opt.)}, number = {3}, doi = {10.1364/ao.36.000635}, pages = {635 -- 641}, abstract = {We investigate a system of two waveguides with leaky modes sharing a common substrate (radiatively coupled waveguides). The main advantage of such a system is the possibility of remote coupling. A perturbation theory is developed for both TE and TM polarization. Numerical calculations of dispersion curves and of the coupling length allow us to determine the limitations of the perturbation theory. We study the influence of multimode interference on the process of beating by considering the propagation of a given initial field. Finally, we propose a new design for an effective, integrated optical TE-TM polarization splitter.}, language = {en} } @misc{SorokinStepanovVasilievetal., author = {Sorokin, Vladislav V. and Stepanov, Gennady V. and Vasiliev, V. G. and Kramarenko, Elena Yu and Mayer, Matthias and Shamonin (Chamonine), Mikhail and Monkman, Gareth J.}, title = {Investigation of Dynamic Modulus and Normal Force of Magnetorheological Elastomers with Soft and Hard Magnetic Fillers}, series = {NANO 2014, July 13 - 18, 2014, Moscow ; Section 06 - Polymer, Organic and Other Soft Matter Materials}, journal = {NANO 2014, July 13 - 18, 2014, Moscow ; Section 06 - Polymer, Organic and Other Soft Matter Materials}, address = {Moscow}, language = {en} } @inproceedings{ForsterMayerRabindranathetal., author = {Forster, Eva and Mayer, Matthias and Rabindranath, Raman and Bentz, Alexander and B{\"o}se, Holger and Shamonin (Chamonine), Mikhail and Monkman, Gareth J.}, title = {Surface Control Magneto-Active Polymers (MAP)}, series = {EuroEAP 2011, First international conference on Electromechanically Active Polymer (EAP) transducers \& artificial muscles, Pisa, 8-9 June}, booktitle = {EuroEAP 2011, First international conference on Electromechanically Active Polymer (EAP) transducers \& artificial muscles, Pisa, 8-9 June}, abstract = {Smart materials change their properties with external energy supply. Besides the known ferro-fluids and Magneto Rheological Fluid (MRF) also the Electro Active Polymer (EAP) and Magneto Rheological Elastomer (MRE) belong to these intelligent materials. The latest generation of magnetic elastomers represents a new class of composite materials. This consists of small magnetized particles which are sized in the micron or even nanometer range that in turn is bounded in a highly elastic rubber matrix. These materials are very often called MRE. Only recently, it has managed to develop these materials even further, so that very soft composite materials with a young?s modulus up to 10 kPa are possible. These soft polymers could be named magneto-active polymers. The combination of polymers with magnetic materials show novel and often enhanced properties. A precisely controllable young?s modulus and hardness, giant and non-homogeneous deformation behavior and rapid response to the magnetic field opens up new possibilities for various applications. Since MAP represent a very new technology, the behavior of these materials as a function of their composition and external conditions so far are not yet sufficiently understood. Therefore, some fundamental studies are necessary. In this paper, the mechanical surface properties are studied using a micro hardness meter. This work shows the possibility to control mechanical properties at the surface of MAP with new developed magnetic systems.}, language = {en} } @article{RadkovskayaSydorukShamoninChamonineetal., author = {Radkovskaya, Anna A. and Sydoruk, O. and Shamonin (Chamonine), Mikhail and Shamonina, Ekaterina and Stevens, C. J. and Faulkner, Grahame and Edwards, David J. and Solymar, L.}, title = {Experimental study of a bi-periodic magnetoinductive waveguide: comparison with theory}, series = {IET Microwaves, Antennas \& Propagation}, volume = {1}, journal = {IET Microwaves, Antennas \& Propagation}, number = {1}, publisher = {IET}, issn = {1751-8733}, doi = {10.1049/iet-map:20050289}, pages = {80 -- 83}, abstract = {Magnetoinductive waves propagating along a line consisting of two kinds of metamaterial elements are studied. Both elements are made up by the same metallic loop but are loaded by different capacitors resulting in different resonant frequencies. The dispersion characteristics are derived from phase and amplitude measurements for the cases when the line consists of (i) identical elements and (ii) of alternating elements. Both planar (elements in the same plane as the axis of the line) and axial (elements perpendicular to the axis of the line) configurations are investigated. It is shown that in the bi-periodic arrangement of the elements, the dispersion curves have a forward wave in the lower frequency branch and a backward wave in the upper frequency branch independent of the configuration whether it is planar or axial. Comparisons between theoretical and experimental results show good agreement.}, language = {en} } @inproceedings{MayerForsterRabindranathetal., author = {Mayer, Matthias and Forster, Eva and Rabindranath, Raman and Bentz, Alexander and B{\"o}se, Holger and Shamonin (Chamonine), Mikhail and Monkman, Gareth J.}, title = {Highly compliant Magneto-Active Polymers (MAPs)}, series = {Actuator'11, Bremen, May 2011}, booktitle = {Actuator'11, Bremen, May 2011}, language = {en} } @article{SydorukShamoninChamonineRadkovskayaetal., author = {Sydoruk, O. and Shamonin (Chamonine), Mikhail and Radkovskaya, Anna A. and Zhuromskyy, Oleksandr and Shamonina, Ekaterina and Trautner, Ralph and Stevens, C. J. and Faulkner, Grahame and Edwards, David J. and Solymar, L.}, title = {Mechanism of subwavelength imaging with bilayered magnetic metamaterials: Theory and experiment}, series = {Journal of Applied Physics}, volume = {101}, journal = {Journal of Applied Physics}, number = {7}, publisher = {AIP}, doi = {10.1063/1.2714782}, abstract = {We present a theoretical and experimental study of a bilayered metamaterial structure for subwavelength imaging of magnetic field. The simplest version of such a structure consists of one or two linear arrays of capacitively loaded split pipe resonators. Its subwavelength physics is governed by strongly anisotropic magnetic coupling between individual resonators and by propagation of magnetoinductive waves with wavelength much shorter than the wavelength of the electromagnetic radiation in free space. It is shown that magnetoinductive waves propagating in the lateral direction are undesirable because they spread the image. Good subwavelength imaging is achieved when, due to the strong interlayer coupling, a stop band in the vicinity of the resonant frequency appears in the dispersion characteristics. The imaging properties of the single and double lens are compared and it is shown that the double lens has a superior performance. Excellent agreement is obtained between experimental and theoretical results for the magnetic field in the image plane in the operation frequency range of 30-60 MHz. It is shown that the same mechanism is responsible for image formation using bilayered planar metamaterial structures and a design of such a lens comprising two planar layers with a total of 542 elements is provided. The conclusions are not restricted to the radio frequency region because the elements can be scaled down.}, language = {en} } @article{RadkovskayaSydorukShamoninChamonineetal., author = {Radkovskaya, Anna A. and Sydoruk, O. and Shamonin (Chamonine), Mikhail and Stevens, C. J. and Faulkner, Grahame and Edwards, David J. and Shamonina, Ekaterina and Solymar, L.}, title = {Transmission properties of two shifted magnetoinductive waveguides}, series = {Microwave and Optical Technology Letters}, volume = {49}, journal = {Microwave and Optical Technology Letters}, number = {5}, publisher = {Wiley}, doi = {10.1002/mop.22344}, pages = {997 -- 1230}, abstract = {Transmission properties of magnetoinductive waves propagating in two coupled one-dimensional metamaterial arrays are studied both experimentally and theoretically for the case when one of the arrays is shifted relative to the other one. Two different kinds of resonant metamaterial elements, split-pipe and spiral resonators, are investigated in the frequency bands centred at 46.2 and 586 MHz, respectively. It is shown that within a certain frequency range close to the resonant frequencies the transmission is strongly dependent on the shift. Theoretical calculations based on the impedance matrix show good agreement with the experimental results}, language = {en} } @inproceedings{ForsterRabindranathMayeretal., author = {Forster, Eva and Rabindranath, Raman and Mayer, Matthias and Bentz, Alexander and B{\"o}se, Holger and Shamonin (Chamonine), Mikhail and Monkman, Gareth J.}, title = {Characterization of ultra soft Magneto-Active Polymers (MAPs)}, series = {Conference proceedings / INDUCTICA 2011, Berlin, Germany, 24 - 26 May}, booktitle = {Conference proceedings / INDUCTICA 2011, Berlin, Germany, 24 - 26 May}, language = {en} } @article{SavelevGlavanBelanetal., author = {Savelev, Dmitrii V. and Glavan, Gašper and Belan, Viktoria O. and Belyaeva, Inna A. and Fetisov, Leonid Y. and Shamonin (Chamonine), Mikhail}, title = {Resonant Magnetoelectric Effect at Low Frequencies in Layered Polymeric Cantilevers Containing a Magnetoactive Elastomer}, series = {Applied Sciences}, volume = {12}, journal = {Applied Sciences}, number = {4}, publisher = {MPDI}, doi = {10.3390/app12042102}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-30637}, pages = {1 -- 13}, abstract = {In this work, the resonance enhancement of magnetoelectric (ME) coupling at the two lowest bending resonance frequencies was investigated in layered cantilever structures comprising a magnetoactive elastomer (MAE) slab and a commercially available piezoelectric polymer multilayer. A cantilever was fixed at one end in the horizontal plane and the magnetic field was applied horizontally. Five composite structures, each containing an MAE layer of different thicknesses from 0.85 to 4 mm, were fabricated. The fundamental bending resonance frequency in the absence of a magnetic field varied between roughly 23 and 55 Hz. It decreased with the increasing thickness of the MAE layer, which was explained by a simple theory. The largest ME voltage coefficient of about 7.85 V/A was measured in a sample where the thickness of the MAE layer was ≈2 mm. A significant increase in the bending resonance frequencies in the applied DC magnetic field of 240 kA/m up to 200\% was observed. The results were compared with alternative designs for layered multiferroic structures. Directions for future research were also discussed.}, language = {en} } @article{FetisovChashinSavelevetal., author = {Fetisov, Yuri K. and Chashin, Dmitri V. and Savelev, Dmitrii V. and Fetisov, Leonid Y. and Shamonin (Chamonine), Mikhail}, title = {Anisotropic Magnetoelectric Effect in a Planar Heterostructure Comprising Piezoelectric Ceramics and Magnetostrictive Fibrous Composite}, series = {Materials}, volume = {12}, journal = {Materials}, number = {19}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/ma12193228}, pages = {1 -- 13}, abstract = {The direct magnetoelectric (ME) effect is investigated in a planar structure comprising mechanically coupled layers of a magnetostrictive fibrous composite (MFC) and a piezoelectric ceramics (lead zirconate titanate, PZT). The MFC is an array of Ni-wires with a diameter of 200 mu m that are aligned parallel to each other in a single layer. The wires are separated by a distance of 250 or 500 mu m and fixed in a polyamide matrix. The structure was placed in a tangential constant field H and was excited by an alternating magnetic field h parallel to H, while the voltage generated by the PZT layer was measured. The resulting field dependences of the magnetization M(H) and the magnetostriction lambda(H) were determined by the orientation of the field H in the plane of the structure and the distance between the Ni-wires. The ME coupling coefficient of the structure decreased from 4.8 to 0.25 V/A when the orientation of H was changed from parallel to perpendicular to Ni-wires. With an increase in the excitation field amplitude h, a nonlinear ME effect in the output voltage, namely frequency doubling, was observed. The frequency and field dependences of the efficiency of the ME transduction in the MFC-piezoelectric heterostructure are well described by the existing theory.}, language = {en} } @techreport{RabindranathBoeseProbstetal., author = {Rabindranath, Raman and B{\"o}se, Holger and Probst, J{\"o}rn and Schlunck, G{\"u}nther and Mayer, Matthias and Forster, Eva and Bentz, Alexander and Shamonin (Chamonine), Mikhail and Monkman, Gareth J.}, title = {EAP mit magnetisch steuerbarer Elastizit{\"a}t zur Interaktion mit Bindegewebszellen MagElan}, address = {Regensburg}, organization = {Hochschule f{\"u}r Angewandte Wissenschaften Regensburg / Fachbereich Elektro- und Informationstechnik}, pages = {37}, language = {de} } @article{SavelevChashinFetisovetal., author = {Savelev, Dmitrii V. and Chashin, Dmitri V. and Fetisov, Leonid Y. and Shamonin (Chamonine), Mikhail and Fetisov, Yuri K.}, title = {Ceramic-Heterostructure-Based Magnetoelectric Voltage Transformer with an Adjustable Transformation Ratio}, series = {Materials}, volume = {13}, journal = {Materials}, number = {18}, publisher = {MDPI}, doi = {10.3390/ma13183981}, pages = {1 -- 13}, abstract = {A voltage transformer employing the magnetoelectric effect in a composite ceramic heterostructure with layers of a magnetostrictive nickel-cobalt ferrite and a piezoelectric lead zirconate-titanate is described. In contrast to electromagnetic and piezoelectric transformers, a unique feature of the presented transformer is the possibility of tuning the voltage transformation ratio K using a dc magnetic field. The dependences of the transformer characteristics on the frequency and the amplitude of the input voltage, the strength of the control magnetic field and the load resistance are investigated. The transformer operates in the voltage range between 0 and 112 V, and the voltage transformation ratio K is tuned between 0 and 14.1 when the control field H changes between 0 and 6.4 kA/m. The power at the transformer output reached 63 mW, and the power conversion efficiency was 34\%. The methods for calculation of the frequency response, and the field and load characteristics of the transformer are proposed. The ways to improve performance characteristics of magnetoelectric transformers and their possible application areas are discussed.}, language = {en} } @article{RomeisKostrovKramarenkoetal., author = {Romeis, Dirk and Kostrov, Sergei A. and Kramarenko, Elena Yu and Stepanov, Gennady V. and Shamonin (Chamonine), Mikhail and Saphiannikova, Marina}, title = {Magnetic-field-induced stress in confined magnetoactive elastomers}, series = {Soft Matter}, volume = {16}, journal = {Soft Matter}, number = {39}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, doi = {10.1039/D0SM01337D}, pages = {9047 -- 9058}, abstract = {We present a theoretical approach for calculating the state of stress induced by a uniform magnetic field in confined magnetoactive elastomers of arbitrary shape. The theory explicitly includes the magnetic field generated by magnetizable spherical inclusions in the sample interior assuming a non-linear magnetization behavior. The initial spatial distribution of particles and its change in an external magnetic field are considered. This is achieved by the introduction of an effective demagnetizing factor where both the sample shape and the material microstructure are taken into account. Theoretical predictions are fitted to the stress data measured using a specifically designed experimental setup. It is shown that the theory enables the quantification of the effect of material microstructure upon introducing a specific microstructural factor and its derivative with respect to the extensional strain in the undeformed state. The experimentally observed differences between isotropic and anisotropic samples, compliant and stiff elastomer matrices are explained.}, language = {en} } @article{SnarskiiShamoninChamonineYuskevichetal., author = {Snarskii, Andrei A. and Shamonin (Chamonine), Mikhail and Yuskevich, Pavel and Savelev, Dmitrii V. and Belyaeva, Inna A.}, title = {Induced anisotropy in composite materials with reconfigurable microstructure: Effective medium model with movable percolation threshold}, series = {Physica A: Statistical Mechanics and its Applications}, volume = {560}, journal = {Physica A: Statistical Mechanics and its Applications}, number = {December}, publisher = {Elsevier}, doi = {10.1016/j.physa.2020.125170}, abstract = {In composite materials, with field-dependent restructuring of the filler material (changes in the mutual arrangement of inclusions), the presence of an external magnetic field induces anisotropy of the dielectric properties, even if the composite is isotropic in the absence of an external field. A modified effective medium approximation is proposed for the calculation of the components of effective permittivity within a class of composites with reconfigurable microstructure, where both phases (the filler and the matrix) are isotropic and the inclusions have spherical shape. The effective physical properties are calculated in the parallel and perpendicular directions to an applied field. The appearance of the anisotropy of the permittivity is simulated by the introduction of two not-equal, possibly variable (field-dependent) percolation thresholds. The implications, of the proposed theoretical approach, are demonstrated for the case of the dielectric properties of magnetoactive elastomers (MAEs). In MAEs with soft polymer matrices, the mutual arrangement of micrometer-sized magnetic inclusions can significantly change in an applied magnetic field. A reasonable agreement between theory and experiment at a measurement frequency of 1 kHz is found, and is improved in comparison to the previous models. The components of the effective permittivity tensor, characterizing the dielectric properties along the direction of the applied magnetic field and in the orthogonal direction, grow with an increasing field. This growth is more pronounced for the permittivity component in the field direction. The possible extensions of the theoretical model and future directions of research are discussed. The presented theoretical approach can be useful for the application-driven development of a number of smart materials, in particular electro- and magnetorheological gels, elastomers and fluids.}, language = {en} } @article{GlavanBelyaevaRuwischetal., author = {Glavan, Gašper and Belyaeva, Inna A. and Ruwisch, Kevin and Wollschlaeger, Joachim and Shamonin (Chamonine), Mikhail}, title = {Magnetoelectric Response of Laminated Cantilevers Comprising a Magnetoactive Elastomer and a Piezoelectric Polymer, in Pulsed Uniform Magnetic Fields}, series = {Sensors}, volume = {21}, journal = {Sensors}, number = {19}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s21196390}, pages = {1 -- 19}, abstract = {The voltage response to pulsed uniform magnetic fields and the accompanying bending deformations of laminated cantilever structures are investigated experimentally in detail. The structures comprise a magnetoactive elastomer (MAE) slab and a commercially available piezoelectric polymer multilayer. The magnetic field is applied vertically and the laminated structures are customarily fixed in the horizontal plane or, alternatively, slightly tilted upwards or downwards. Six different MAE compositions incorporating three concentrations of carbonyl iron particles (70 wt\%, 75 wt\% and 80 wt\%) and two elastomer matrices of different stiffness are used. The dependences of the generated voltage and the cantilever's deflection on the composition of the MAE layer and its thickness are obtained. The appearance of the voltage between the electrodes of a piezoelectric material upon application of a magnetic field is considered as a manifestation of the direct magnetoelectric (ME) effect in a composite laminated structure. The ME voltage response increases with the increasing total quantity of the soft-magnetic filler in the MAE layer. The relationship between the generated voltage and the cantilever's deflection is established. The highest observed peak voltage around 5.5 V is about 8.5-fold higher than previously reported values. The quasi-static ME voltage coefficient for this type of ME heterostructures is about 50 V/A in the magnetic field of approximate to 100 kA/m, obtained for the first time. The results could be useful for the development of magnetic field sensors and energy harvesting devices relying on these novel polymer composites.}, language = {en} } @article{SavelevBelyaevaChashinetal., author = {Savelev, Dmitrii V. and Belyaeva, Inna A. and Chashin, Dmitri V. and Fetisov, Leonid Y. and Romeis, Dirk and Kettl, Wolfgang and Kramarenko, Elena Yu and Saphiannikova, Marina and Stepanov, Gennady V. and Shamonin (Chamonine), Mikhail}, title = {Giant extensional strain of magnetoactive elastomeric cylinders in uniform magnetic fields}, series = {Materials}, volume = {13}, journal = {Materials}, number = {15}, publisher = {MDPI}, address = {Basel}, issn = {1996-1944}, doi = {10.3390/ma13153297}, pages = {1 -- 17}, abstract = {Elongations of magnetoactive elastomers (MAEs) under ascending-descending uniform magnetic fields were studied experimentally using a laboratory apparatus specifically designed to measure large extensional strains (up to 20\%) in compliant MAEs. In the literature, such a phenomenon is usually denoted as giant magnetostriction. The synthesized cylindrical MAE samples were based on polydimethylsiloxane matrices filled with micrometer-sized particles of carbonyl iron. The impact of both the macroscopic shape factor of the samples and their magneto-mechanical characteristics were evaluated. For this purpose, the aspect ratio of the MAE cylindrical samples, the concentration of magnetic particles in MAEs and the effective shear modulus were systematically varied. It was shown that the magnetically induced elongation of MAE cylinders in the maximum magnetic field of about 400 kA/m, applied along the cylinder axis, grew with the increasing aspect ratio. The effect of the sample composition is discussed in terms of magnetic filler rearrangements in magnetic fields and the observed experimental tendencies are rationalized by simple theoretical estimates. The obtained results can be used for the design of new smart materials with magnetic-field-controlled deformation properties, e.g., for soft robotics.}, language = {en} } @article{SavelevFetisovChashinetal., author = {Savelev, Dmitrii V. and Fetisov, Leonid Y. and Chashin, Dmitri V. and Fetisov, Yuri K. and Khon, Anastasia and Shamonin (Chamonine), Mikhail}, title = {Effects of ferromagnetic-material thickness on magnetoelectric voltage transformation in a multiferroic heterostructure}, series = {Smart Materials and Structures}, volume = {30}, journal = {Smart Materials and Structures}, number = {6}, publisher = {IOP PUBLISHING}, doi = {10.1088/1361-665X/abf6c0}, abstract = {A magnetoelectric (ME) voltage transformer is fabricated on the basis of a ferromagnetic (FM)-piezoelectric (PE) heterostructure comprising two equally thick laminated layers of an amorphous FM alloy and a piezoceramic lead zirconate-titanate layer sandwiched between them. The structure, placed inside an excitation coil, is electrically poled and magnetized in the direction of the long axis. The primary voltage is applied to the coil and the secondary voltage is measured between the electrodes of the PE material. It is shown for the first time that the change in the total thickness of magnetic layers significantly influences the transformer ' s characteristics. At the largest total thickness of FM layers of 138 mu m, the open-circuit voltage transformation ratio K has a maximum value of about 20, and the power transfer efficiency eta at a matched resistive load of about 20 k omega reaches 45\%. The variation of the control magnetic field in the range of 0-21.6 kA m(-1) makes it possible to change the voltage transformation ratio K from zero to the maximum value. A simple model allows one to calculate the dependence of the characteristics of the ME transformer on the frequency of the primary voltage, thickness of the FM layers, control magnetic field, and the load.}, language = {en} } @article{SavelevBelyaevaChashinetal., author = {Savelev, Dmitrii V. and Belyaeva, Inna A. and Chashin, Dmitri V. and Fetisov, Leonid Y. and Shamonin (Chamonine), Mikhail}, title = {Large Wiedemann effect in a magnetoactive elastomer}, series = {Journal of Magnetism and Magnetic Materials}, volume = {511}, journal = {Journal of Magnetism and Magnetic Materials}, number = {October}, publisher = {Elsevier}, doi = {10.1016/j.jmmm.2020.166969}, abstract = {Large twists of a soft tube (hollow cylinder) in helical magnetic fields are presented for the first time. Such a phenomenon is usually denoted as the Wiedemann effect. The tube is fabricated from a soft magnetoactive elastomer material with the shear modulus of about 56 kPa. The composite material comprises 80 mass\% of micrometer-sized iron particles embedded into a polydimethylsiloxane matrix. The circular magnetic field is generated by an electric current in a straight wire passing through the inner hole of the tube. The maximum value of approximately 350″/cm is observed in a longitudinal magnetic field of a few kA/m overlapped with a circumferential magnetic field of about 1.4 kA/m on the surface of the inner hole. A pronounced hysteresis in the dependence of the Wiedemann effect on the circular magnetic field is found. The ways to enhance the Wiedemann twist in magnetoactive elastomers are discussed. The observed large effect is promising for application in magnetic-field controlled torsional actuators, in particular for soft robotics.}, language = {en} } @article{SavelevFetisovChashinetal., author = {Savelev, Dmitrii V. and Fetisov, Leonid Y. and Chashin, Dmitri V. and Shabin, P. A. and Vyunik, D. A. and Fedulov, Feodor and Kettl, Wolfgang and Shamonin (Chamonine), Mikhail}, title = {Method of Measuring Deformations of Magnetoactive Elastomers under the Action of Magnetic Fields}, series = {Russian Technological Journal}, volume = {7}, journal = {Russian Technological Journal}, number = {4}, doi = {10.32362/2500-316x-2019-7-4-81-91}, pages = {81 -- 91}, language = {ru} } @misc{PershinaSavelevGlavanetal., author = {Pershina, K. V. and Savelev, Dmitrii V. and Glavan, Gašper and Chashin, Dmitri V. and Belyaeva, Inna A. and Fetisov, Leonid Y. and Shamonin (Chamonine), Mikhail}, title = {The voltage response of a structure comprising a magnetoactive-elastomer cylinder and a piezoelectric material to magnetic field step excitations}, series = {The 4th International Baltic Conference on Magnetism (IBCM 2021) : Svetlogorsk, Russia August 29 - September 2, 2021 : Book of Abstracts}, journal = {The 4th International Baltic Conference on Magnetism (IBCM 2021) : Svetlogorsk, Russia August 29 - September 2, 2021 : Book of Abstracts}, publisher = {Immanuel Kant Baltic Federal University, Kaliningrad, Russia}, pages = {182}, language = {en} } @article{DillingerWeberMayeretal., author = {Dillinger, Andrea Elisabeth and Weber, Gregor R. and Mayer, Matthias and Schneider, Magdalena and G{\"o}ppner, Corinna and Ohlmann, Andreas and Shamonin (Chamonine), Mikhail and Monkman, Gareth J. and Fuchshofer, Rudolf and Keller, Kate and Lozano, Diana C. and Clark, Abbot}, title = {CCN2/CTGF-A Modulator of the Optic Nerve Head Astrocyte}, series = {Frontiers in cell and developmental biology (Front Cell Dev Biol.)}, volume = {10}, journal = {Frontiers in cell and developmental biology (Front Cell Dev Biol.)}, publisher = {frontiers}, doi = {10.3389/fcell.2022.864433}, pages = {864433}, abstract = {In primary open-angle glaucoma (POAG), a neurodegenerative disease of the optic nerve (ON) and leading cause of blindness, the optic nerve head (ONH) undergoes marked structural extracellular matrix (ECM) changes, which contribute to its permanent deformation and to degeneration of ON axons. The remodeling process of the ECM causes changes in the biomechanical properties of the ONH and the peripapillary sclera, which is accompanied by an increased reactivity of the resident astrocytes. The molecular factors involved in the remodeling process belong to the Transforming growth factor (TGF)-β superfamily, especially TGF-β2. In previous publications we showed that TGF-β2 induced ECM alterations are mediated by Cellular Communication Network Factor (CCN)2/Connective Tissue Growth Factor (CTGF) and recently we showed that CCN2/CTGF is expressed by astrocytes of the ON under normal conditions. In this study we wanted to get a better understanding of the function of CCN2/CTGF under normal and pathologic conditions. To this end, we analyzed the glial lamina and peripapillary sclera of CCN2/CTGF overexpressing mice and studied the effect of CCN2/CTGF and increasing substratum stiffness on murine ON astrocytes in vitro. We observed enhanced astrocyte reactivity in the ONH, increased ECM protein synthesis in the peripapillary sclera and increased Ccn2/Ctgf expression in the ONH during the pathologic development in situ. CCN2/CTGF treatment of primary murine ON astrocytes induced a higher migration rate, and increase of ECM proteins including fibronectin, elastin and collagen type III. Furthermore, the astrocytes responded to stiffer substratum with increased glial fibrillary acidic protein, vimentin, actin and CCN2/CTGF synthesis. Finally, we observed the reinforced appearance of CCN2/CTGF in the lamina cribrosa of glaucomatous patients. We conclude that reactive changes in ONH astrocytes, induced by the altered biomechanical characteristics of the region, give rise to a self-amplifying process that includes increased TGF-β2/CCN2/CTGF signaling and leads to the synthesis of ECM molecules and cytoskeleton proteins, a process that in turn augments the stiffness at the ONH. Such a scenario may finally result in a vicious circle in the pathogenesis of POAG. The transgenic CTGF-overexpressing mouse model might be an optimal model to study the chronic pathological POAG changes in the ONH.}, language = {en} } @article{PandeyViljoenWayetal., author = {Pandey, Mahesh and Viljoen, Celeste and Way, Andrew and Katharina Fischer, Katharina and S{\´y}kora, Miroslav and Diamantidis, Dimitris and Steenbergen, Rapha{\"e}l D.J.M. and Lind, Niels and Frangopol, Dan M. and Yang, David Y. and Retief, Johan Verster and Andr{\´e}, Jo{\~a}o and Nathwani, Jatin and Lenner, Roman}, title = {Life safety in the Reliability-Based design and assessment of structures}, series = {Structural Safety}, journal = {Structural Safety}, publisher = {Elsevier}, doi = {10.1016/j.strusafe.2024.102453}, abstract = {We review the developments in life safety and the incorporation thereof in the design and assessment of structures over the last 50 years. Various measures of life safety are presented that have been developed according to the marginal life saving cost principle based on individual, societal and economic considerations. Target probabilities of failure, or target reliabilities, are central to modern structural design and assessment. These are derived either through back-calibration to existing practice or through life cycle cost minimisation, both of which yield comparable safety levels, and are underpinned by lower bounds from life safety. Life cycle cost minimisation is reviewed here, which considers all direct and indirect costs of failure including loss of life and limb, as well as the costs and efficiency of increasing reliability. We discuss the incorporation of life safety into reliability-based design and assessment through the concept of the Life Quality Index, which uses key societal indicators, namely, the GDP and life expectancy, and health economics as a basis for specifying minimum reliabilities for both new and existing structures. The current state of advancement of reliability- and risk-informed design, and recommendations for future developments in life safety are considered.}, language = {en} } @article{SavelevGlavanBurdinetal., author = {Savelev, Dmitrii V. and Glavan, Gašper and Burdin, Dmitrii A. and Belyaeva, Inna A. and Fetisov, Leonid Y. and Shamonin (Chamonine), Mikhail and Fetisov, Yuri K.}, title = {Enhancement of magnetoelectric effect in polymer composites at low resonance frequencies by operation in the transverse-transverse mode}, series = {Journal of Magnetism and Magnetic Materials}, volume = {598}, journal = {Journal of Magnetism and Magnetic Materials}, publisher = {Elsevier}, issn = {1873-4766}, doi = {10.1016/j.jmmm.2024.172020}, abstract = {The resonant direct magnetoelectric (ME) effect for a series of multilayer heterostructures comprising a magnetoactive elastomer (MAE) of different thicknesses and a commercially available piezoelectric polyvinylidene fluoride-based vibration sensor has been investigated in detail. The specimens were rigidly fixed at one end as cantilevers. The cantilevers were operated in the transverse-transverse (T-T) mode, where both magnetic and electric fields were perpendicular to the plane of a non-deformed heterostructure. It is shown that the ME voltage coefficient of considered heterostructures in the T-T mode can be about 20-fold higher than in the conventional longitudinal-transverse (L-T) mode. The highest ME voltage coefficient reached about 150 V/(Oe·cm) at the first bending oscillation mode for the sample with MAE layer thickness of 4 mm. Mechanism of the resonant ME effect in T-T mode is explained using theory of critical bending of MAE cantilevers. Magnetic fields, when the ME voltage reaches its maximum, strongly depended on the MAE layer thickness, and could be associated with the critical field, where the structure commences to strongly bend. The non-monotonous dependence of the resonance frequency of the first oscillation mode on magnetic field strength was observed. The shift of the resonance frequency in the maximum magnetic field reached up to roughly 100 \% in comparison with zero field.}, language = {en} } @misc{Kriegl, author = {Kriegl, Raphael}, title = {Characterization of Wetting Properties of Magnetoactive Elastomer Surfaces [Data set]}, doi = {10.5281/zenodo.13124610}, language = {en} } @article{GlavanBelyaevaShamoninChamonine, author = {Glavan, Gašper and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail}, title = {Multiferroic Cantilevers Containing a Magnetoactive Elastomer: Magnetoelectric Response to Low-Frequency Magnetic Fields of Triangular and Sinusoidal Waveform}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {10}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s22103791}, pages = {1 -- 17}, abstract = {In this work, multiferroic cantilevers comprise a layer of a magnetoactive elastomer (MAE) and a commercially available piezoelectric polymer-based vibration sensor. The structures are fixed at one end in the horizontal plane and the magnetic field is applied vertically. First, the magnetoelectric (ME) response to uniform, triangle-wave magnetic fields with five different slew rates is investigated experimentally. Time and field dependences of the generated voltage, electric charge, and observed mechanical deflection are obtained and compared for four different thicknesses of the MAE layer. The ME responses to triangular and sinusoidal wave excitations are examined in contrast. Second, the ME response at low frequencies (≤3 Hz) is studied by the standard method of harmonic magnetic field modulation. The highest ME coupling coefficient is observed in the bias magnetic field strength of ≈73 kA/m and it is estimated to be about 3.3 ns/m (ME voltage coefficient ≈ 25 V/A) at theoretically vanishing modulation frequency (f→0 Hz). Presented results demonstrate that the investigated heterostructures are promising for applications as magnetic-field sensors and energy harvesting devices.}, language = {en} } @misc{Kriegl2022, author = {Kriegl, Raphael}, title = {Microstructured Magnetoactive Elastomers for Switchable Wettability [Data set]}, doi = {10.5281/zenodo.13124555}, year = {2022}, language = {en} } @article{GeldofKopačinStrausetal., author = {Geldof, Arne and Kopačin, Jan and Straus, Izidor and Kriegl, Raphael and Kravanja, Gaia and Hribar, Luka and Jezeršek, Matija and Shamonin, Mikhail and Kokot, Gašper and Drevenšek-Olenik, Irena}, title = {Transfer of Energy and Momentum Between Magnetoactive Surface Microstructure and a Solid Object}, series = {Advanced Engineering Materials}, volume = {28}, journal = {Advanced Engineering Materials}, number = {6}, publisher = {Wiley}, doi = {10.1002/adem.202502369}, pages = {9}, abstract = {Transport systems utilizing magnetic materials are very promising for applications that require contactless operation and compatibility with biological processes. A critical parameter in these systems is the efficiency of energy and momentum transfer between the transporting platform and the objects being transported. We investigate the physical mechanisms driving directional transport of solid objects by microlamellar structures laser-inscribed on the surface of a magnetoactive elastomer (MAE). When subjected to a rotating magnetic field with a magnitude of 175 mT and a time period of 0.4 s, the lamellas reorient within a few milliseconds, reaching angular velocities up to 1100 rad s-1. This rapid motion is crucial for efficient momentum and energy transfer to objects in contact with the lamellas. The analysis of collisions of a single lamella with a lead ball with a 2.2 mm diameter shows that the lamella can transfer around 50 nJ of energy, propelling the ball to a speed of around 35 mm s-1. We show how this value sets the upper limit for the ball's transport speed on microlamellar structures. We also explain the background of three distinct transport regimes (kicking, pushing, and bouncing modes) observed on these magnetically driven "conveyor belts".}, language = {en} }