@misc{RodriguezCalcerradaSalomonGordalizaetal., author = {Rodr{\´i}guez-Calcerrada, Jes{\´u}s and Salom{\´o}n, Roberto L. and Gordaliza, Guillermo G. and Miranda, Jos{\´e} C. and Garcia de la Riva, Enrique and Gil, Luis}, title = {Respiratory costs of producing and maintaining stem biomass in eight co-occurring tree species}, series = {Tree Physiology}, volume = {39}, journal = {Tree Physiology}, number = {11}, issn = {1568-2544}, doi = {10.1093/treephys/tpz069}, pages = {1838 -- 1854}, language = {en} } @misc{OssorioVinuesaGarciaetal., author = {Ossorio, {\´O}scar G. and Vinuesa, Guillermo and Garcia, Hector and Sahelices, Benjamin and Due{\~n}as, Salvador and Cast{\´a}n, Helena and P{\´e}rez, Eduardo and Mahadevaiah, Mamathamba Kalishettyhalli and Wenger, Christian}, title = {Performance Assessment of Amorphous HfO2-based RRAM Devices for Neuromorphic Applications}, series = {ECS Transactions}, volume = {102}, journal = {ECS Transactions}, number = {2}, issn = {1938-6737}, doi = {10.1149/10202.0029ecst}, pages = {29 -- 35}, abstract = {The use of thin layers of amorphous hafnium oxide has been shown to be suitable for the manufacture of Resistive Random-Access memories (RRAM). These memories are of great interest because of their simple structure and non-volatile character. They are particularly appealing as they are good candidates for substituting flash memories. In this work, the performance of the MIM structure that takes part of a 4 kbit memory array based on 1-transistor-1-resistance (1T1R) cells was studied in terms of control of intermediate states and cycle durability. DC and small signal experiments were carried out in order to fully characterize the devices, which presented excellent multilevel capabilities and resistive-switching behavior.}, language = {en} } @misc{MartreDueriGuarinetal., author = {Martre, Pierre and Dueri, Sibylle and Guarin, Jose Rafael and Ewert, Frank and Webber, Heidi and Calderini, Daniel and Molero, Gemma and Reynolds, Matthew and Miralles, Daniel and Garcia, Guillermo and Brown, Hamish and George, Mike and Craigie, Rob and Cohan, Jean-Pierre and Deswarte, Jean-Charles and Slafer, Gustavo A. and Giunta, Francesco and Cammarano, Davide and Ferrise, Roberto and Gaiser, Thomas and Gao, Yujing and Hochman, Zvi and Hoogenboom, Gerrit and Hunt, Leslie A. and Kersebaum, Kurt C. and Nendel, Claas and Padovan, Gloria and Ruane, Alex C. and Srivastava, Amit Kumar and Stella, Tommaso and Supit, Iwan and Thorburn, Peter and Wang, Enli and Wolf, Joost and Zhao, Chuang and Zhao, Zhigan and Asseng, Senthold}, title = {Global needs for nitrogen fertilizer to improve wheat yield under climate change}, series = {Nature Plants}, volume = {10}, journal = {Nature Plants}, number = {7}, publisher = {Springer Science and Business Media LLC}, issn = {2055-0278}, doi = {10.1038/s41477-024-01739-3}, pages = {1081 -- 1090}, language = {en} } @misc{VinuesaGarciaDuenasetal., author = {Vinuesa, Guillermo and Garcia, Hector and Duenas, Salvador and Castan, Helena and I{\~n}iguez de la Torre, Ignacio and Gonzalez, Tomas and Dorai Swamy Reddy, Keerthi and Uhlmann, Max and Wenger, Christian and Perez, Eduardo}, title = {Effect of the temperature on the performance and dynamic behavior of HfO2-Based Rram Devices}, series = {ECS Meeting Abstracts}, volume = {MA2024-01}, journal = {ECS Meeting Abstracts}, number = {21}, publisher = {The Electrochemical Society}, issn = {2151-2043}, doi = {10.1149/MA2024-01211297mtgabs}, pages = {1297 -- 1297}, abstract = {Over the past decades, the demand for semiconductor memory devices has been steadily increasing, and is currently experiencing an unprecedented boost due to the development and expansion of artificial intelligence. Among emerging high-density non-volatile memories, resistive random-access memory (RRAM) is one of the best recourses for all kind of applications, such as neuromorphic computing or hardware security [1]. Although many materials have been evaluated for RRAM development, some of them with excellent results, HfO2 is one of the established materials in CMOS domain due to its compatibility with standard materials and processes [2]. The main goal of this work is to study the switching capability and stability of HfO2-based RRAMs, as well as to explore their ability in the field of analogue applications, by analyzing the evolution of the resistance states that allow multilevel control. Indeed, analogue operation is a key point for achieving electronic neural synapses in neuromorphic systems, with synaptic weight information encoded in the different resistance states. This research has been carried out over a wide temperature range, between 40 and 340 K, as we are interested in testing the extent to which performance is maintained or modified, with a view to designing neuromorphic circuits that are also suitable in the low-temperature realm. We aim to prove that these simple, fast, high integration density structures can also be used in circuits designed for specific applications, such as aerospace systems. The RRAM devices studied in this work are TiN/Ti/8 nm-HfO2/TiN metal-insulator-metal (MIM) capacitors. Dielectric layers were atomic layer deposited (ALD). It has been demonstrated that the Ti coat in the top electrode acts as a scavenger that absorbs oxygen atoms from the HfO2 layer, and facilitates the creation of conductive filaments of oxygen vacancies [3]. In fact, the oxygen reservoir capability of Ti is well known, as it is able to attract and release oxygen atoms from or to the HfO2 layer during the RRAM operation [4]. The clustering of vacancies extends through the entire thickness of the oxide and, after an electroformig step, it joins the upper and lower electrodes and the device reaches the low resistance state (LRS). By applying adequate electrical signals, the filaments can be partially dissolved, which brings the device into the high-resistance state (HRS), with lower current values. The set process brings the device to the LRS state, while the reset one brings it to the HRS. The dependence of electrical conductivity on external applied electrical excitation allows triggering the device between the both states in a non-volatile manner [5]. The experimental equipment used consisted of a Keithley 4200-SCS semiconductor parameter analyzer and a Lake Shore cryogenic probe station. Fig.1 shows current-voltage cycles measured at different temperatures; the averages values at each temperature, both in logarithmic and linear scale, are also shown. The functional window increases as temperature decreases. The evolutions of set and reset voltage values with temperature are depicted in Fig.2, whereas the current values (measured at 0.1 V) corresponding to the LRS and HRS can be seen in Fig.3. LRS resistance decreases as temperature increases, in agreement with semiconductor behaviour, probably due to a hopping conduction mechanism. Both set and reset voltages decrease as temperature increases; the reset process is smoother at high temperatures. The reduction in reset voltage variability as temperature increases is very notable. Finally, Fig. 4 shows a picture of the transient behaviour; in the right panel of the same figure, the amplitudes of the current transients in the reset state have been included in the external loop. To sum up, the resistive switching phenomena is studied in a wide temperature range. The LRS shows semiconducting behavior with temperature, most likely related to a hopping conduction mechanism. Switching voltages decrease as temperature increases, with a notable reduction in reset voltage variability. An excellent control of intermediate resistance state is shown through current transients at several voltages in the reset process. REFERENCES [1] M. Asif et al., Materials Today Electronics 1, 100004 (2022). [2] S. Slesazeck et al., Nanotechnology 30, 352003 (2019). [3] Z. Fang et al., IEEE Electron Device Letters 35, 9, 912-914 (2014). [4] H. Y. Lee et al., IEEE Electron Device Letters 31, 1, 44-46 (2010). [5] D. J. Wouters et al., Proceedings of the IEEE 103, 8, 1274-1288 (2015). Figure 1}, language = {en} } @misc{StellaWebberRezaeietal., author = {Stella, Tommaso and Webber, Heidi and Rezaei, Ehsan Eyshi and Asseng, Senthold and Martre, Pierre and Dueri, Sibylle and Guarin, Jose Rafael and Pequeno, Diego and Calderini, Daniel and Reynolds, Matthew and Molero, Gemma and Miralles, Daniel and Garcia, Guillermo and Slafer, Gustavo A. and Giunta, Francesco and Kim, Yean-Uk and Wang, Chenzhi and Ruane, Alex C. and Ewert, Frank}, title = {Wheat crop traits conferring high yield potential may also improve yield stability under climate change}, series = {in silico Plants}, volume = {5}, journal = {in silico Plants}, number = {2}, publisher = {Oxford University Press (OUP)}, issn = {2517-5025}, doi = {10.1093/insilicoplants/diad013}, pages = {16}, abstract = {Increasing genetic wheat yield potential is considered by many as critical to increasing global wheat yields and production, baring major changes in consumption patterns. Climate change challenges breeding by making target environments less predictable, altering regional productivity and potentially increasing yield variability. Here we used a crop simulation model solution in the SIMPLACE framework to explore yield sensitivity to select trait characteristics (radiation use efficiency [RUE], fruiting efficiency and light extinction coefficient) across 34 locations representing the world's wheat-producing environments, determining their relationship to increasing yields, yield variability and cultivar performance. The magnitude of the yield increase was trait-dependent and differed between irrigated and rainfed environments. RUE had the most prominent marginal effect on yield, which increased by about 45 \% and 33 \% in irrigated and rainfed sites, respectively, between the minimum and maximum value of the trait. Altered values of light extinction coefficient had the least effect on yield levels. Higher yields from improved traits were generally associated with increased inter-annual yield variability (measured by standard deviation), but the relative yield variability (as coefficient of variation) remained largely unchanged between base and improved genotypes. This was true under both current and future climate scenarios. In this context, our study suggests higher wheat yields from these traits would not increase climate risk for farmers and the adoption of cultivars with these traits would not be associated with increased yield variability.}, language = {en} } @misc{DeTomasMarinRodriguezCalcerradaArenasCastroetal., author = {De Tom{\´a}s Mar{\´i}n, Sergio and Rodr{\´i}guez-Calcerrada, Jes{\´u}s and Arenas-Castro, Salvador and Prieto, Iv{\´a}n and Gonz{\´a}lez, Guillermo and Gil, Luis and Garcia de la Riva, Enrique}, title = {Fagus sylvatica and Quercus pyrenaica: Two neighbors with few things in common}, series = {Forest Ecosystems}, volume = {10}, journal = {Forest Ecosystems}, issn = {2197-5620}, doi = {10.1016/j.fecs.2023.100097}, language = {en} }