TY - CONF A1 - Kreutzbruck, Marc T1 - Phased Array-Based SAFT for Defect Sizing on Power Plant Components T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) CY - Chicago, IL, USA DA - 2008-07-20 PY - 2008 AN - OPUS4-18110 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Lembke, G. A1 - Mogwitz, B. A1 - Korte, C. A1 - Janek, J. T1 - Linear magnetoresistance in Ag2+deltaSe thin films N2 - In the nonstoichiometric low-temperature phase of silver selenide a very small silver excess within the semiconducting silver selenide matrix in the order of 0.01% is sufficient to generate a linear magnetoresistance (LMR) of more than 300% at 5 T, which does not saturate at fields up to 60 T. Different theoretical models have been proposed to explain this unusual magnetoresistance (MR) behavior, among them a random resistor network consisting of four-terminal resistor units. According to this model the LMR and the crossover field from linear to quadratic behavior are primarily controlled by both the spatial distribution of the charge-carrier mobility and its average value, being essentially functions of the local and average compositions. Here we report measurements on silver-rich thin AgxSe films with a thickness between 20 nm and 2 µm, which show an increasing average mobility in conjunction with an enhanced MR for increasing film thickness. We found a linear scaling between the size of the transverse LMR and the crossover field, as predicted by the theory. For films thinner than about 100 nm the MR with field directed in the sample plane shows a breakdown of the LMR, revealing the physical length scale of the inhomegeneities in thin AgxSe devices. KW - Carrier mobility KW - Magnetoresistance KW - Semiconductor materials KW - Semiconductor thin films KW - Silver vompounds KW - Stoichiometry PY - 2009 DO - https://doi.org/10.1103/PhysRevB.79.035204 SN - 1098-0121 SN - 0163-1829 SN - 0556-2805 SN - 1095-3795 SN - 1550-235X VL - 79 IS - 3 SP - 035204-1 - 035204-5 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-18930 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - GMR sensors for Nondestructive Testing - Recent Developments in Sensor based Eddy Current and Magnetic Flux Leakage Testing T2 - 10th Symposium Magnetoresistive Sensors and Magnetic Systems CY - Wetzlar, Germany DA - 2009-03-31 PY - 2009 AN - OPUS4-19038 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kienle, L. A1 - Duppel, V. A1 - Mogwitz, B. A1 - Korte, C. A1 - Kreutzbruck, Marc A1 - Janek, J. T1 - Real structures and structural modifications of Ag2+xSe thin films KW - Ag clusters KW - MR KW - LT PY - 2007 DO - https://doi.org/10.1017/S1431927607082013 SN - 1431-9276 SN - 1435-8115 VL - 13 IS - Suppl 3 SP - 402 EP - 403 PB - Cambridge University Press CY - New York, NY AN - OPUS4-19242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Advanced Crack Shape Analysis Using SAFT T2 - Non-destructive Evaluation 2009, Non-destructive Evaluation in Power Industry CY - Tiruchirappalli, India DA - 2009-12-10 PY - 2009 AN - OPUS4-20058 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kervalishvili, Guram N. A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - FEM modelling of heat transfer in the vicinity of vertical surface cracks using local thermal excitation T2 - Thermographie-Kolloquium 2009 CY - Stuttgart, Germany DA - 2009-10-08 KW - FEM modelling KW - Active thermography KW - Laser excitation KW - Cracks KW - Steel PY - 2009 IS - DGZfP-BB 119-CD (Poster 02) SP - 1 EP - 8 CY - Berlin AN - OPUS4-20096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetic Response Field of Spherical Defects within Conductive Components T2 - 5th International Workshop Non-Destructive Testing in Progress CY - Prague, Czech Republic DA - 2009-10-12 PY - 2009 AN - OPUS4-20152 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. T1 - Inverse algorithm for electromagnetic wire inspection based on GMR-sensor arrays N2 - To meet the increasing fabrication quality standards and the high throughput requirements NDE techniques are reliant on efficient reconstruction tools and visualization tools. In this work we present an inverse algorithm for a modern electromagnetic non-destructive testing approach using a small GMR sensor array to inspect superconducting wires. Four sensitive GMR sensors are positioned around the wire. Small defects of 100 µm in size could be detected in a depth of 200 µm with a signal-to-noise ratio of better than 400. Surface defects could be detected with a SNR of up to 10,000. This remarkably SNR and the small extent of GMR sensors results in a spatial resolution which offers new visualisation techniques for defect localisation, defect characterization and future tomography-like mapping techniques. We developed several inverse algorithms based on either a Finite Element Method or an analytical approach leading to defect localization with an accuracy of a few 10 µm. KW - Nondestructive testing KW - Reconstruction KW - GMR-sensor array KW - Superconducting wires PY - 2009 DO - https://doi.org/10.3233/JAE-2009-1030 SN - 1383-5416 SN - 0925-2096 VL - 30 IS - 3-4 SP - 299 EP - 308 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-20273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Defect sizing by local excitation thermography T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Thermography KW - Laser excitation KW - FEM modeling KW - Crack sizing PY - 2009 SN - 978-80-214-3968-9 SP - 261 EP - 270 AN - OPUS4-20333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Völz, Uwe A1 - Mrasek, Heinz A1 - Matthies, Klaus A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Visualization of sound propagation with electrodynamic probes T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic KW - Sound field KW - Visualization KW - Electrodynamic probe KW - Nondestructive testing (NDT) KW - Nickel alloy KW - Anisotropic weld KW - Narrow-gap weld PY - 2009 SN - 978-80-214-3968-9 SP - 321 EP - 328 AN - OPUS4-20334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gaal, Mate A1 - Döring, Joachim A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Detection of flaws with lamb waves and air-coupled ultrasound T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Lamb waves KW - Air-coupled probes KW - Beam profile KW - Ultrasonic testing PY - 2009 SN - 978-80-214-3968-9 SP - 53 EP - 58 AN - OPUS4-20335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kreutzbruck, Marc A1 - Thomas, Hans-Martin A1 - Casperson, Ralf A1 - Reimund, Verena A1 - Blome, Mark A1 - Allweins, K. A1 - Lembke, G. ED - Mazal, Pavel T1 - Magnetic response field of spherical defects within conductive components T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Electromagnetic testing KW - Spherical defects KW - Finite element method PY - 2009 SN - 978-80-214-3968-9 SP - 163 EP - 172 AN - OPUS4-20336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schenk, Gottfried A1 - Brackrock, Daniel A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc A1 - Deutsch, W.A.K. A1 - Joswig, M. A1 - Maxam, K. A1 - Schuster, V. ED - Mazal, Pavel T1 - Ultrasonic inspection system for automated round-bar-testing based on phased array technique T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic testing KW - Phased array KW - Round bar testing PY - 2009 SN - 978-80-214-3968-9 SP - 253 EP - 259 AN - OPUS4-20338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Prager, Jens A1 - Hoever, Carsten A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Flaw detection with guided waves using phased array technique T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic testing KW - Guided waves KW - Plate-like structures PY - 2009 SN - 978-80-214-3968-9 SP - 203 EP - 212 AN - OPUS4-20339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Heckel, Thomas A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc A1 - Rühe, S. ED - Mazal, Pavel T1 - High speed non-destructive rail testing with advanced ultrasound and eddy-current testing techniques T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Non-destructive testing (NDT) KW - Rail inspection KW - Ultrasound KW - Eddy current KW - Signal processing PY - 2009 SN - 978-80-214-3968-9 SP - 101 EP - 109 AN - OPUS4-20340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kitze, Jessica A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc ED - Mazal, Pavel T1 - Saft for crack surface analysis - Comparison of modeling and phased array measurements T2 - 5th International workshop of NDT experts - NDT in progress 2009 CY - Prague, Czech Republic DA - 2009-10-12 KW - Ultrasonic testing KW - SAFT KW - Phased array PY - 2009 SN - 978-80-214-3968-9 SP - 1 EP - 10 AN - OPUS4-20341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heckel, Thomas A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc A1 - Rühe, S. T1 - High speed non-destructive rail testing with advanced ultrasound and eddy-current testing techniques N2 - Today the rails face increased exposure to heavy loads, higher speeds and a very dense overall traffic. A continued development of testing methods for the rail inspection trains became necessary to match the modern needs for a fast detection and detailed classification of defects. To guarantee the safe operation of rail traffic non-destructive inspection techniques with combined ultrasound and eddy current testing methods are used to detect damages on rails. One of the main actual challenges of automated rail testing is the high inspection speed which is very close to the physical limits. To overcome these limits digital signal processing algorithms have to be used which maintain resolution and detection quality independent of operation speed. This paper presents a recently developed state of the art rail inspection system which uses advanced ultrasonic and eddy current testing techniques. Testing results are shown in a newly developed so called Glassy-Rail-Diagram which is capable to present data with a fixed resolution independent of inspection speed. T2 - NDE 2009 CY - Tiruchirappalli, India DA - 2009-12-10 KW - Non-destructive testing (NDT) KW - Rail inspection KW - Ultrasound KW - Eddy current KW - Signal processing PY - 2009 SP - 261 EP - 265 AN - OPUS4-20883 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Thomas, Hans-Martin A1 - Casperson, Ralf A1 - Reimund, Verena A1 - Blome, Mark A1 - Allweins, K. A1 - Lembke, G. T1 - Magnetic response field of spherical defects on non-destructive evaluation T2 - NDE 2009 CY - Tiruchirappalli, India DA - 2009-12-10 KW - Electromagnetic testing KW - Spherical defects KW - Finite element method PY - 2009 SP - 271 EP - 275 AN - OPUS4-20831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kitze, Jessica A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - The SAFT approach for advanced crack analysis T2 - NDE 2009 CY - Tiruchirappalli, India DA - 2009-12-10 PY - 2009 SP - 315 EP - 318 AN - OPUS4-20832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Völz, Uwe A1 - Kreutzbruck, Marc A1 - Mrasek, Heinz A1 - Matthies, Klaus T1 - Visualization of sound propagation in solids using electrodynamic probes N2 - When dealing in ultrasonic testing with inhomogeneous material structure data interpretation can be rather difficult. This is especially the case when using anisotropic dissimilar welds made from austenitic steel or nickel based alloys, which are currently used for modern power plant concepts. In this work we present an electrodynamic technique to visualize sound waves with frequencies up to 3 MHz in steel components providing a simple use and a high signal-to-noise ratio. By detecting the grazing beam with an electrodynamic probe, we measured the particle displacement as a function of time with a spatial resolution in the order of 1 mm. Adapting the electrodynamic probe and its coil alignment allows for measuring the displacement components in all three dimensions. This comprises the detection of the horizontal and vertical particle displacement with respect to the surface and thus also the transformation from longitudinal waves into transversal waves and vice versa. We report on measurements of the sound field in a complex narrow-gap weld, joining a nickel alloy with a chrome steel with a substantial anisotropy of the weld structure. The test system enables us to visualize the wave propagation within the weld and indicates the reflection scenario and the energy losses due to both the anisotropic structure and material defects. T2 - IEEE International Ultrasonics Symposium 2009 CY - Rome, Italy DA - 2009-09-19 KW - Acoustic propagation KW - Anisotropic media KW - Nickel alloys KW - Nondestructive testing KW - Visualization PY - 2009 SN - 978-1-4244-4390-1 SN - 1948-5727 SP - 1495 EP - 1498 AN - OPUS4-21126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heckel, Thomas A1 - Kreutzbruck, Marc A1 - Montag, Hans-Joachim A1 - Fenger, S. T1 - The glassy rail: advanced ultrasonic rail inspection PY - 2010 SN - 0976-254X VL - 1 IS - 5 SP - 16 EP - 19 PB - Headliners Advertising Services Pvt. Ltd. CY - Kolkata, India AN - OPUS4-23269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc A1 - Boehm, Rainer A1 - Kitze, Jessica A1 - Eggers, H. A1 - Böwe, M. T1 - Using UT-SAFT for analysis of stress corrosion cracking N2 - Stress corrosion cracking is a transcrystalline or intercrystalline crack formation in materials which occurs under the influence of static tensile stress or residual stress and a specific aggressive medium such as chloride containing substances. This special sort of crack formation is involved in complex crack configurations, which may only insufficiently be captured by conventional ultrasonic probes with fixed angles of incidence. Only a number of different beam angles produce sufficient reflection to reconstruct the complete defect shape from measured ultrasonic data. The SAFT algorithm, which was recently successfully used in many industrial NDT-applications, is a promising tool for the reconstruction process. In addition, the combination of phased array technique and SAFT was developed in several projects by BAM, Berlin. Investigations using phased array equipment were performed to look into crack configurations in test blocks with different surface curvatures. UT-SAFT has been used for the analysis of spark-eroded notches simulating stress corrosion cracks at the thermo sleeve weld of a nozzle. For comparison, UT-SAFT has also been applied for the analysis of real reflectors at the same position in a nozzle used in a power plant, which was repaired later on. SAFT-scans received from reconstructed ultrasonic measurement data confirm the practical usefulness of the SAFTalgorithm developed by BAM. T2 - 8th International conference on NDE in relation to structural integrity for nuclear and pressurised components CY - Berlin, Germany DA - 2010-09-29 KW - Stress corrosion cracking KW - Real and simulated cracks KW - D-nozzle KW - Phased array technique KW - SAFT reconstruction PY - 2010 SN - 978-3-940283-30-6 IS - DGZfP-BB 125 (Th.2.B.1) SP - 1 EP - 10 CY - Berlin AN - OPUS4-23594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Cellular polypropylene ferroelectret film: Piezoelectric material for non-contact Ultrasonic transducers T2 - WCNDT 2008 CY - Shanghai, China DA - 2008-10-25 PY - 2008 AN - OPUS4-18171 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - High Resolution Eddy Current Testing of Superconducting Wires using GMR-Sensors T2 - WCNDT 2008 CY - Shanghai, China DA - 2008-10-25 PY - 2008 AN - OPUS4-18172 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Quantitative Defect Sizing on Components with Different Wall Thickness using UT-SAFT T2 - WCNDT 2008 CY - Shanghai, China DA - 2008-10-25 PY - 2008 AN - OPUS4-18173 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Bernau, H. ED - Peter Scharff, T1 - Inverse Algorithm for Electromagnetic Wire Inspection based on GMR-Sensor Arrays T2 - 10th Workshop on optimization and inverse problems in electromagnetism (OIPE 2008) CY - Ilmenau, Germany DA - 2008-09-14 KW - Nondestructive Testing KW - Reconstruction KW - GMR-sensor array KW - Superconducting wires PY - 2008 IS - O6_1 SP - 137 EP - 138 CY - Ilmenau AN - OPUS4-18367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. T1 - High Resolution Eddy Current Testing of Superconducting Wires using GMR-Sensors T2 - 17th World Conference on Non-Destructive Testing CY - Shanghai, China DA - 2008-10-25 KW - GMR-sensor KW - Eddy Current Testing KW - Reconstruction KW - Superconducting wires PY - 2008 IS - Paper 389 SP - 1 EP - 6 PB - International Committee for Non-Destructive Testing CY - Shanghai AN - OPUS4-18434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Joachim A1 - Bovtun, V. A1 - Bartusch, Jürgen A1 - Beck, Uwe A1 - Kreutzbruck, Marc T1 - Cellular polypropylene ferroelectret film: piezoelectric material for non-contact ultrasonic transducers T2 - 17th World Conference on Non-Destructive Testing CY - Shanghai, China DA - 2008-10-25 KW - Air-coupled ultrasound KW - Ultrasonic transducers KW - Electromechanical properties KW - Piezoelectric materials KW - Impedance spectroscopy PY - 2008 IS - Paper 123 SP - 1 EP - 6 PB - International Committee for Non-Destructive Testing CY - Shanghai AN - OPUS4-18435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brekow, Gerhard A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kreutzbruck, Marc T1 - Quantitative Defect Sizing on Components with Different Wall Thickness using UT-SAFT T2 - 17th World Conference on Non-Destructive Testing CY - Shanghai, China DA - 2008-10-25 KW - UT-SAFT KW - Reconstruction PY - 2008 IS - Paper 122 SP - 1 EP - 6 PB - International Committee for Non-Destructive Testing CY - Shanghai AN - OPUS4-18436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Hochauflösende Wirbelstromprüfung - Ein Streifzug durch anspruchsvolle Prüfprobleme am Rande dreier Nobelpreise T2 - DGZfP - Arbeitskreis, 84. Sitzung CY - Zwickau, Germany DA - 2008-10-21 PY - 2008 AN - OPUS4-19258 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetische Mikrosysteme für die Hochauflösende Wirbelstromprüfung - Ein Streifzug durch anspruchsvolle Prüfsysteme am Rande dreier Nobelpreise T2 - DGZfP-Arbeitskreis Niedersachsen 355. Sitzung CY - Wolfsburg, Germany DA - 2009-04-23 PY - 2009 AN - OPUS4-19337 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brekow, Gerhard A1 - Brackrock, Daniel A1 - Boehm, Rainer A1 - Kreutzbruck, Marc ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Phased array-based SAFT for defect sizing on power plant components N2 - Quantitative NDE methods play a key role when it comes to inspect components, which requires high operational safety. UT-SAFT is one of the well-known reconstruction tools, which provides information about the defect size. In this work we studied the use of phased array technique in combination with the SAFT algorithm to inspect power plant components. As a first example we inspected a real-sized mock-up model representing a part of a reactor pressure vessel with a 180 mm-thick ferritic base material followed by a 6 mm-thick austenitic cladding layer. The phased array probe was coupled at the outer ferritic surface. We detected and sized fatigue cracks within the cladding with a depth ranging from 4 mm to 10 mm. Secondly, we investigated a mock-up model resembling a nozzle including a thermo sleeve inlet and a maximum wall thickness of about 37 mm. Artificially inserted notches with a depth of 3 mm could be detected and sized, where the thermo sleeve is welded at the inside of the nozzle. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Ultrasonic testing KW - Phased arrays KW - SAFT KW - Power plant components PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 872 EP - 879 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völz, Uwe A1 - Mrasek, Heinz A1 - Matthies, Klaus A1 - Wüstenberg, Hermann A1 - Kreutzbruck, Marc ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Electrodynamic approach for visualization of sound propagation in solids N2 - The visualization of sound propagation in solids is vital for transducer adaptation and better understanding of complex test samples and their wave propagation modeling. In this work we present an electrodynamic technique detecting the grazing sound beam with a 10 mm-sized electrodynamic probe. The particle displacement along the sample’s surface was then measured as a function of time and position. Adapting the electrodynamic probe and its coil alignment allows for measuring the displacement components in all three dimensions. Thus horizontal and vertical particle displacement with respect to the surface can be detected. A SNR of up to 40 dB could be achieved within ferromagnetic and high conductive chrome steel when using a shear wave generated by an angle beam probe. When dealing with nonconductive materials such as PMMA we obtained a reduced SNR of 12 dB. We report on measurements of the sound field in complex weld joints. One example shows a narrow gap weld joining a nickel alloy with a chrome steel. The weld of the 80 mm-thick test block shows a distinct anisotropic texture. The system enables us to visualize the wave propagation within the weld and indicates the reflection and scattering scenario and the energy losses due to both the anisotropic structure and material defects. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Ultrasonic KW - Sound field KW - Visualization KW - Electrodynamic probe KW - Nondestructive testing KW - Nickel alloy KW - Anisotropic weld KW - Narrow gap weld PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 758 EP - 765 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc A1 - Allweins, K. A1 - Strackbein, C. A1 - Bernau, H. ED - Thompson, D. O. ED - Chimenti, D. E. T1 - High resolution eddy-current wire testing based on a GMR sensor-array N2 - Increasing demands in materials quality and cost effectiveness have led to advanced standards in manufacturing technology. Especially when dealing with high quality standards in conjunction with high throughput quantitative NDE techniques are vital to provide reliable and fast quality control systems. In this work we illuminate a modern electromagnetic NDE approach using a small GMR sensor array for testing superconducting wires. Four GMR sensors are positioned around the wire. Each GMR sensor provides a field sensitivity of 200 pT/√Hz and a spatial resolution of about 100 µm. This enables us to detect under surface defects of 100 µm in size in a depth of 200 µm with a signal-to-noise ratio of better than 400. Surface defects could be detected with a SNR of up to 10,000. Besides this remarkably SNR the small extent of GMR sensors results in a spatial resolution which offers new visualisation techniques for defect localisation, defect characterization and tomography-like mapping techniques. We also report on inverse algorithms based on either a Finite Element Method or an analytical approach. These allow for accurate defect localization on the µm scale and an estimation of the defect size. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - GMR KW - Eddy current testing KW - Reconstruction KW - FEM PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 1695 EP - 1702 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Arndt, Ralf A1 - Kreutzbruck, Marc ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Influence of surface properties on the detection and quantification of voids in concrete structures using active thermography N2 - Impulse thermography is an active method for quantitative investigations of the near surface region of various structures. It has recently been applied and optimized to applications in civil engineering. For quantitative analysis of data recorded on the building site, the problems are manifold. Here, the influence of the different surface properties on the detection and characterization of voids and honeycombing simulated by polystyrene cubes and cubes prepared of porous concrete are demonstrated. T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Active thermography KW - Pulse phase thermography KW - Surface properties KW - Emissivity KW - Concrete KW - Voids KW - Honeycombing PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 1505 EP - 1511 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-19438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dohse, Elmar A1 - Kreutzbruck, Marc A1 - Schenk, Gottfried T1 - Vom "Logikgrab" zur Einchip-Lösung: Der Einsatz von FPGAs in digitalen Ultraschallgeräten T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - Ultraschall KW - Gerätetechnik PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 ( Poster 36) SP - 1 EP - 2 AN - OPUS4-20515 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Prager, Jens A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Fehlernachweis mit Plattenwellen und Luftultraschall T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - Plattenwellen KW - Luftultraschall KW - Ultraschallprüfung PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 ( Di.1.A.2) SP - 1 EP - 7 AN - OPUS4-20516 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Boehm, Rainer A1 - Brackrock, Daniel A1 - Kitze, Jessica A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - SAFT für die Rissflächenanalyse - Vergleich von Modellrechnungen und Gruppenstrahlermessungen T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - SAFT KW - Rissflächenanalyse PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Mi.3.A.2) SP - 1 EP - 11 AN - OPUS4-20518 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hoever, Carsten A1 - Prager, Jens A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Fehlernachweis mit geführten Wellen unter Verwendung der Gruppenstrahlertechnik T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 KW - Geführte Wellen KW - Gruppenstrahlertechnik PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Poster 35) SP - 1 EP - 8 AN - OPUS4-20519 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreutzbruck, Marc A1 - Thomas, Hans-Martin A1 - Sickert, Roland A1 - Casperson, Ralf A1 - Boehm, Rainer A1 - Allweins, K. A1 - Lemke, G. T1 - A numerical study of the inclusion problem in electromagnetic testing KW - FEM KW - Eddy Current Testing (ECT) KW - Eddy Current (EC) PY - 2009 SN - 0025-5300 VL - 51 IS - 11-12 SP - 819 EP - 827 PB - Hanser CY - München AN - OPUS4-20507 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Kreutzbruck, Marc T1 - Spektroskopische Untersuchungen an Polypropylen-Schaumfolie mit Luftultraschall T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Poster 39) SP - 1 EP - 2 AN - OPUS4-20509 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kreutzbruck, Marc T1 - Magnetic Response Field of Spherical Defects within Conductive Components T2 - NDE 2009, NDE in Power Industry CY - Tiruchirappalli, India DA - 2009-12-10 PY - 2009 AN - OPUS4-20565 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Defect sizing by local excitation thermography T2 - 15th International conference "Building services, mechanical and building industry days" CY - Debrecen, Hungary DA - 2009-10-15 KW - Thermography KW - Laser excitation KW - FEM Modeling KW - Crack sizing PY - 2009 SN - 978-963-473-315-7 SP - 67 EP - 76 AN - OPUS4-20655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Prager, Jens A1 - Hoever, C. A1 - Kreutzbruck, Marc T1 - Untersuchungen zur Anregung geführter Wellen in Platten mittels Gruppenstrahlertechnik N2 - Geführte Wellen breiten sich in Platten und Hohlzylindern über weite Entfernungen aus. Aus dieser Eigenschaft ergibt sich ein hohes Anwendungspotential dieser Wellenart für die zerstörungsfreie Prüfung ausgedehnter Bauteile und Strukturen mittels Ultraschall. Nachteilig für die Anwendung geführter Wellen sind ihr dispersives Verhalten und die zunehmende Anzahl ausbreitungsfähiger Wellenmoden bei hohen Frequenzen. Ziel des Einsatzes der Gruppenstrahlertechnik ist es, eine ausgewählte Wellenmode selektiv anzuregen bzw. zu empfangen. Durch die Änderung des Schwenkwinkels im Gruppenstrahlerprüfkopf wird eine definierte Spurwellenlänge auf dem Interface zwischen Prüfkopf und Struktur festgelegt, die zur Anregung einer Welle mit entsprechender Phasengeschwindigkeit führt. Da der Schwenkwinkel elektronisch verändert werden kann, lässt sich auch die angeregte Wellenmode elektronisch auswählen, worin der große Vorteil des vorgestellten Verfahrens liegt. In den vorgestellten Untersuchungen wurde die Anwendbarkeit der Methode experimentell demonstriert. Der Anregemechanismus wurde theoretisch beleuchtet und die Wellenausbreitung im Prüfkopf mit verschiedenen analytischen Ansätzen modelliert. Mit diesen Modellen können Fragen der Richtwirkung und der Effizienz der Anregung detailliert untersucht werden. Die modellierten Wellenfelder wurden mit den experimentellen Ergebnissen verglichen und die Anwendbarkeit der theoretischen Ansätze beurteilt, wobei die Ergebnisse der theoretischen Untersuchungen im Experiment verifiziert werden konnten. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (P41) SP - 1 EP - 5 CY - Berlin AN - OPUS4-21883 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schenk, Gottfried A1 - Brackrock, Daniel A1 - Boehm, Rainer A1 - Kreutzbruck, Marc A1 - Deutsch, W.A.K. A1 - Joswig, M. A1 - Maxam, K. A1 - Schuster, V. T1 - Untersuchungen zum Einfluss von Geometrie- und Temperaturabweichungen bei der Stangenprüfung mit Ultraschall-Gruppenstrahlertechnik N2 - Bei der automatisierten Prüfung von Stangen mit Ultraschall- Gruppenstrahlertechnik besteht grundsätzlich die Möglichkeit, Prüfkopfparameter wie Einschallwinkel, Fokustiefe und Schallbündelbreite programmgesteuert an sich verändernde Prüfbedingungen anzupassen. Zu diesen zählt die Temperatur des Koppelmediums (Wasser), die in einem Bereich von 10°C bis 50°C liegen kann, was zu unterschiedlichen Schallgeschwindigkeiten führt und den Einschallwinkel verändert. Mit der Folge, dass unter Umständen die geforderte 100%-Abdeckung des Prüfvolumens nicht mehr gewährleistet ist. Auch geometrische Abweichungen, wie sie durch die fertigungsbedingte Streuung des Prüflings gegeben sind, können Einfluss auf das Prüfergebnis nehmen. So führen Abweichungen vom idealen Geradheitszustand zu Fehlpositionierungen des Prüfkopfs, was wiederum Einfluss auf die Lage und Beschaffenheit des Schallbündels in der Stange hat. Ähnliches gilt für nicht vollkommen kreisförmig ausgebildete Stangendurchmesser, die unterschiedliche Schalleintrittsbedingungen bewirken und Abweichungen von den theoretisch ermittelten Werten zur Folge haben. Im Rahmen eines vom BMWi geförderten Forschungsvorhabens wurde der Einfluss dieser Parameter untersucht und ihre Auswirkungen für den Betrieb einer automatisierten Prüfanlage unter realen Betriebsbedingungen ermittelt. Dies betrifft vor allem den maximal möglichen Schallbündelversatz innerhalb des Arrays, der die Anzahl der erforderlichen Prüftakte bestimmt und damit die maximale Vorschubgeschwindigkeit des Prüflings. Des Weiteren werden Möglichkeiten zur programmgesteuerten Kompensation der untersuchten Temperatur- und Geometrieabweichungen durch eine flexible Anpassung der Gruppenstrahler- Prüfkopfparameter aufgezeigt. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mi.4.A.1) SP - 1 EP - 8 CY - Berlin AN - OPUS4-21878 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kitze, Jessica A1 - Brackrock, Daniel A1 - Brekow, Gerhard A1 - Prager, Jens A1 - Gaal, Mate A1 - Kreutzbruck, Marc A1 - Szabo, D. A1 - Kuti, K. A1 - Paczolay, G. T1 - SAFT und TOFD - Ein Vergleich im Analyseverhalten von Reflektoren N2 - Mit der Gruppenstrahlertechnik der Bundesanstalt für Materialforschung und -prüfung sind umfangreiche Untersuchungen an einer plattierten Druckbehälter-Testwand durchgeführt worden. In der vorliegenden Testwand mit einer Wanddicke von 149 mm befinden sich künstliche Testreflektoren im Schweißnaht- und Plattierungsbereich, die mit Gruppenstrahler- Prüfköpfen mit unterschiedlichen Frequenzen, Einschallwinkeln und Einschallrichtungen nachgewiesen und in ihrem Anzeigenverhalten analysiert wurden. Zur Rekonstruktion der Reflektoranzeigen wurde ein SAFT - Algorithmus verwendet, der die Variation der Einschallwinkel berücksichtigt. Zum Vergleich sind die Reflektoren auch mit der TOFD - Technik analysiert worden. Ziel der Untersuchungen war der direkte Vergleich der Eignung der SAFT- und TOFDTechnik zur quantitativen Reflektorgrößenbestimmung. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mi.2.A.3) SP - 1 EP - 11 CY - Berlin AN - OPUS4-21880 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias A1 - Reimund, Verena A1 - Blome, Mark A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc T1 - 3D-GMR-Messung an Referenzbauteilen und Rekonstruktion der Rissparameter N2 - Zunehmend werden hochpräzise Magnetfeldsensoren in der Materialprüfung verwendet. Aus dem Zoo der Magnetfeldsensoren eignen sich GMR-Sensoren (Giant Magneto Resistance) aufgrund ihrer hohen Feld- Empfindlichkeit, ihrem hohen Signal-Rausch-Verhältnis sowie ihrer kleinen Sensorflächen (verbunden mit einer hohen Ortsauflösung) hierfür im Besonderen. Mit GMR-Sensoren wurden Risse untersucht und konnten mit einer Tiefe ≤ 50 µm noch mit einem guten Signal-Rausch-Verhältnis aufgelöst werden. Die an Prüfkörpern mit künstlich eingebrachten Defekten gemessenen Streufeldsignale wurden anhand von analytischen Lösungen verifiziert. Anhand der analytischen Lösungen wurden auch Defektparameter zu den aufgezeichneten Signalen rekonstruiert. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mo.3.A.4) SP - 1 EP - 9 CY - Berlin AN - OPUS4-21881 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Geometrische Charakterisierung von Fehlstellen mittels lokal angeregter aktiver Thermografie N2 - In diesem Beitrag wird eine Methode zur Charakterisierung von offenen Oberflächenrissen mittels aktiver Thermografie präsentiert. Hierzu wird die Probe ortsfest lokal mit einem Laser erwärmt und die resultierende Oberflächentemperatur mittels Infrarotkamera aufgenommen. Bei einer ungestörten Probe ergibt sich ein rotationssymmetrisches Temperaturprofil. Betrachtet man hingegen einen Bereich mit einem Oberflächenriss, so kommt es durch die Störung des lateralen Wärmetransports zu einer unsymmetrischen Temperaturverteilung. Durch die quantitative Analyse diese Unsymmetrie lassen sich Aussagen über geometrische Parameter des Risses treffen. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Mi.1.C.2) SP - 1 EP - 8 CY - Berlin AN - OPUS4-21869 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlichting, Joachim A1 - Kervalishvili, Guram N. A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Geometrische Charakterisierung von Fehlstellen mittels lokal angeregter aktiver Thermografie / Characterizing geometrical parameters of voids with locally excited active thermography T2 - Sensoren und Messsysteme 2010 - 15. ITG/GMA-Fachtagung CY - Nürnberg, Deutschland DA - 2010-05-18 PY - 2010 SN - 978-3-8007-3260-9 IS - Paper 120 SP - 682 EP - 687 PB - VDE Verlag GmbH CY - Berlin, Offenbach AN - OPUS4-21855 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schlichting, Joachim A1 - Maierhofer, Christiane A1 - Kreutzbruck, Marc T1 - Defect sizing by local excitation thermography N2 - In this article, we present a measurement procedure to gain information about depth and angle of open surface cracks. The method is based on a local excitation with, e.g., a laser. The resulting surface temperature is recorded with an infrared camera. Based on this data, crack-caused anisotropies in the lateral heat flow can be detected and exploited to characterise the cracks. The experimental set-up is based on a Nd:YAG laser. The beam is focused on the test sample by using an optical scanner to generate the required lateral heat flow. The time resolved temperature distribution is recorded with a high-speed infrared camera (InSb FPA, 3 to 5 µm) providing a frame rate of up to 500 Hz. Up to now, only qualitative information was gained from measurements of this type. Whereas the local transient behaviour of temperature distribution provides also quantitative information of the crack parameters. The general concept of the method presented herein has already been published [1], but the mentioned publication is focused on the crack depth only. In this paper, we can show that it is possible to simultaneously resolve the angle and depth and, in particular, the depth of non-perpendicular cracks. T2 - QIRT 10 - 10th International conference on Quantitative InfraRed Thermography CY - Québec, Canada DA - 2010-07-27 KW - FEM KW - Risse KW - Thermografie PY - 2010 UR - http://qirt.gel.ulaval.ca/archives/qirt2010/papers/QIRT%202010-121.pdf SN - 978-2-9809199-1-6 IS - QIRT 2010-121 SP - 773 EP - 780 AN - OPUS4-21957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kienle, L. A1 - Duppel, V. A1 - Lembke, G. A1 - Mogwitz, B. A1 - Janek, J. A1 - Kreutzbruck, Marc A1 - Simon, A. T1 - Microstructure and magnetoresistance of heterogeneous gold-rich Ag3Au1.1Te2 N2 - Dispersions of very small non-magnetic metal particles or inclusions in a non-magnetic semiconductor matrix are well known to produce unusually large and linear magnetoresistance effects. So far these materials were limited to the binary silver-rich chalcogenides Ag2Se and Ag2Te. In this contribution Ag3AuTe2 was selected as a first candidate for a ternary matrix material, thus offering enhanced capabilities for the generation of heterogeneous microstructure and spatially varying composition on the nanoscale. In gold-rich Ag3Au1.1Te2 two kinds of inhomogeneities are present, namely Au deposits with a size on the micron scale and an inhomogeneous distribution of Au and Ag within the matrix. The matrix consists of micron-sized grains with the structure type of Ag3AuTe2 as studied by electron microscopy. Like the binary silver chalcogenide phases, the material also shows a large and linear magnetoresistance effect. The transversal magnetoresistance effect was measured between 20 K and 270 K in magnetic fields up to B = 5 T. The results are discussed on the basis of existing models for a large and linear positive MR effect. KW - Petzite KW - Magnetosensor KW - Electron microscopy KW - Nonstoichiometry KW - Magnetoresistance PY - 2010 DO - https://doi.org/10.1016/j.solidstatesciences.2010.07.029 SN - 1293-2558 SN - 1873-3085 VL - 12 IS - 10 SP - 1770 EP - 1778 PB - Elsevier CY - Amsterdam AN - OPUS4-22281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -