Abstract
Thin epitaxial films of the palladium-rich Pd1−xFex alloy were synthesized and extensively studied as a tunable ferromagnetic material for superconducting spintronics. The (001)-oriented MgO single-crystal substrate and the composition range of x = 0.01–0.07 were chosen to support the epitaxial growth and provide the films with magnetic properties spanning from very soft ferromagnet for memory applications to intermediately soft and moderately hard for the programmable logic and circuit biasing, respectively. Dependences of the saturation magnetization, Curie temperature and three magnetic anisotropy constants on the iron content x were obtained for the first time from the analyses of the magnetometry and ferromagnetic resonance data. The experimental results were discussed based on existing theories of dilute ferromagnetic alloys. Simulation of the hysteresis loops within the Stoner-Wohlfarth model indicates the predominant coherent magnetic moment rotation at cryogenic temperatures. The obtained results were compiled in a database of magnetic properties of a palladium-iron alloy in a single-crystal thin-film form considered as a material for superconducting spintronics.
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Acknowledgements
This work was supported by the RSF (18-12-00459). The authors acknowledged Ryazanov VV, Bol'ginov VV and Stolyarov VS (ISSP of RAS, Chernogolovka) for stimulating discussions and introduction to the subject. TEM study was done using the equipment of Physics and technology of micro- and nanostructures Center at IPM RAS, Nizhny Novgorod. The magnetic properties were measured utilizing the equipment of the PCR Federal Center of Shared Facilities of Kazan Federal University.
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Esmaeili A, Yanilkin IV and Gumarov AI designed and engineered the samples; Yanilkin IV and Vakhitov IR performed the magnetic measurements, while Gabbasov BF and Yusupov RV carried out the FMR measurements; Tatarsky DA prepared the sample for TEM imaging; Yanilkin IV, Yusupov RV and Tagirov LR processed the data and wrote the manuscript. All authors contributed to the general discussion and finalization of the manuscript.
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Igor Yanilkin graduated from Moscow Institute of Physics and Technology (MIPT, Dolgoprudny) in 2010, and received his PhD in 2017 from Kazan National Research Technological University (KNRTU, Russia). In 2015 he became a Researcher of the Solid State Physics Department at Kazan Federal University (KFU, Russia). Nowadays Dr. Yanilkin I is a senior researcher of the Synthesis and Analysis of Thin-Film Structures Lab of KFU, and his research interests include thin films, magnetic nanostructures, thin-film heterostructures, and superconductor/ferromagnet heterostructures.
Roman Yusupov received his PhD in 2000 from Kazan State University (KSU, Russia). In 2005–2008 he was studying various strongly-correlated electron systems by femtosecond laser spectroscopy at Jozef Stefan Institute (Slovenia). Since 2010 he has been an associate professor and in 2014 he became a senior researcher of the Center for Quantum Technologies at KFU. His interest includes time-resolved optics and magnetooptics, thin films, frustrated magnetism, and inhomogeneous states in quantum paramagnets and paraelectrics.
Lenar Tagirov received his PhD in 1981 from KSU, Russia and DSc in 1996 from the National Research Nuclear University (MEPhI, Moscow). In 2008 he was appointed the head of the Solid State Physics Department at KSU. In 2016, he joined Zavoisky Physical-Technical Institute of Kazan Scientific Center of RAS. He leads the research lab “Synthesis and Analysis of Thin-Film Structures”, and his research interests include magnetic nanostructures, thin-film heterostructures, superconductor/ferromagnet heterostructures, and plasmonic metamaterials.
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Esmaeili, A., Yanilkin, I.V., Gumarov, A.I. et al. Epitaxial thin-film Pd1−xFex alloy: a tunable ferromagnet for superconducting spintronics. Sci. China Mater. 64, 1246–1255 (2021). https://doi.org/10.1007/s40843-020-1479-0
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DOI: https://doi.org/10.1007/s40843-020-1479-0