The mechanisms of enhancing spin-orbit torque(SOT) have attracted significant attention, particularly regarding the influence of extrinsic scattering mechanisms on SOT efficiency, as they complement intrinsic contribu...The mechanisms of enhancing spin-orbit torque(SOT) have attracted significant attention, particularly regarding the influence of extrinsic scattering mechanisms on SOT efficiency, as they complement intrinsic contributions. In multilayer systems, extrinsic interfacial scattering, along with scattering from defects or impurities inside the materials, plays a crucial role in affecting the SOT efficiency. In this study, we successfully fabricated high-quality epitaxially grown [Ir/Pt]N superlattices with an increasing number of interfaces using a magnetron sputtering system to investigate the contribution of extrinsic interfacial scattering to SOT efficiency. We measured SOT efficiency through spin-torque ferromagnetic resonance methods and determined the spin Hall angle using the spin pumping technique. Additionally, we calculated spin transparency based on the SOT efficiency and spin Hall angle. Our findings indicate that the values of SOT efficiency, spin Hall angle, and spin transparency are enhanced in the superlattice structure compared to Pt, which we attribute to the increase in interfacial scattering.This research offers an effective strategy for designing and fabricating advanced spintronic devices.展开更多
Negative thermal expansion(NTE)is fascinating,as it involves a material’s volume contraction rather than expansion upon heating.Although NTE lattices typically have highly flexible frameworks,the magnitude of NTE is ...Negative thermal expansion(NTE)is fascinating,as it involves a material’s volume contraction rather than expansion upon heating.Although NTE lattices typically have highly flexible frameworks,the magnitude of NTE is often very small,and they frequently exhibit a narrow temperature range for controllable NTEs.It remains a great challenge to achieve large NTE while maintaining a wide temperature operation range from the currently available materials.Herein,we present a novel PbTiO_(3)(PT)-based perovskite system,(1−x)PbTiO_(3)-xBiYbO_(3),synthesized via a distinctive highpressure and high-temperature technique.Compared with pristine PbTiO_(3)(c/a=1.064),the system exhibited unusual enhanced tetragonalities.Consequently,NTE over an extended temperatureαVαVαV range has been realized in 0.95PbTiO_(3)-0.05BiYbO_(3)(-av=−2.18×10^(−5)K^(−1),300-820 K)and 0.90PbTiO_(3)−0.10BiYbO_(3)(-av=−1.85×10^(−5)K^(−1),300-850 K)compared with that of pristine PbTiO_(3)(-av=−1.99×10^(−5)K^(−1),300-763 K).Our experimental and theoretical studies indicate that the improved tetragonality and expanded NTE temperature range result from larger ionic displacements and an enhanced asymmetric charge distribution,both of which are induced by BiYbO_(3) substitution.The present study presents a new example of an NTE across a broad temperature range,highlighting its potential as an effective thermal expansion compensator.展开更多
基金financially supported by the Science Center of the National Science Foundation of China (Grant No. 52088101)the National Natural Science Foundation of China (Grant Nos. 52161160334, 12274437, 12174426, and 52271237)+1 种基金the Chinese Academy of Sciences (CAS) Project for Young Scientists in Basic Research No. YSBR-084the CAS Youth Interdisciplinary Team。
文摘The mechanisms of enhancing spin-orbit torque(SOT) have attracted significant attention, particularly regarding the influence of extrinsic scattering mechanisms on SOT efficiency, as they complement intrinsic contributions. In multilayer systems, extrinsic interfacial scattering, along with scattering from defects or impurities inside the materials, plays a crucial role in affecting the SOT efficiency. In this study, we successfully fabricated high-quality epitaxially grown [Ir/Pt]N superlattices with an increasing number of interfaces using a magnetron sputtering system to investigate the contribution of extrinsic interfacial scattering to SOT efficiency. We measured SOT efficiency through spin-torque ferromagnetic resonance methods and determined the spin Hall angle using the spin pumping technique. Additionally, we calculated spin transparency based on the SOT efficiency and spin Hall angle. Our findings indicate that the values of SOT efficiency, spin Hall angle, and spin transparency are enhanced in the superlattice structure compared to Pt, which we attribute to the increase in interfacial scattering.This research offers an effective strategy for designing and fabricating advanced spintronic devices.
基金supported by the National Key R&D Program of China(No.2021YFA1400300)the National Natural Science Foundation of China(Nos.22271309,12304268,12425403,and 12261131499)+4 种基金the Beijing Natural Science Foundation(No.F251005)the Chinese Academy of Sciences(No.XDB33000000)Duo Wang acknowledges financial support from the Science and Technology Development Fund from Macao SAR(No.0062/2023/ITP2)the Macao Polytechnic University(No.RP/FCA-03/2023)The synchrotron X-ray powder diffraction experiments were performed at SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute(Nos.2024A1506 and 2024A1695).
文摘Negative thermal expansion(NTE)is fascinating,as it involves a material’s volume contraction rather than expansion upon heating.Although NTE lattices typically have highly flexible frameworks,the magnitude of NTE is often very small,and they frequently exhibit a narrow temperature range for controllable NTEs.It remains a great challenge to achieve large NTE while maintaining a wide temperature operation range from the currently available materials.Herein,we present a novel PbTiO_(3)(PT)-based perovskite system,(1−x)PbTiO_(3)-xBiYbO_(3),synthesized via a distinctive highpressure and high-temperature technique.Compared with pristine PbTiO_(3)(c/a=1.064),the system exhibited unusual enhanced tetragonalities.Consequently,NTE over an extended temperatureαVαVαV range has been realized in 0.95PbTiO_(3)-0.05BiYbO_(3)(-av=−2.18×10^(−5)K^(−1),300-820 K)and 0.90PbTiO_(3)−0.10BiYbO_(3)(-av=−1.85×10^(−5)K^(−1),300-850 K)compared with that of pristine PbTiO_(3)(-av=−1.99×10^(−5)K^(−1),300-763 K).Our experimental and theoretical studies indicate that the improved tetragonality and expanded NTE temperature range result from larger ionic displacements and an enhanced asymmetric charge distribution,both of which are induced by BiYbO_(3) substitution.The present study presents a new example of an NTE across a broad temperature range,highlighting its potential as an effective thermal expansion compensator.
