Coexistence of superconductivity and spin-splitting fields in superconductor/ferromagnetic insulator bilayers of arbitrary thickness
| العنوان: | Coexistence of superconductivity and spin-splitting fields in superconductor/ferromagnetic insulator bilayers of arbitrary thickness |
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| المؤلفون: | Carmen González-Orellana, Mikel Rouco, Tero T. Heikkilä, Elia Strambini, Alberto Hijano, Celia Rogero, Pauli Virtanen, Maria Spies, S. Khorshidian, Nadia Ligato, Francesco Giazotto, F. Sebastian Bergeret, M. Ilyn, Stefan Ilić |
| المساهمون: | Ministerio de Ciencia, Innovación y Universidades (España), Academy of Finland, Agencia Estatal de Investigación (España), Eusko Jaurlaritza, European Research Council, European Commission, Ministerio de Economía y Competitividad (España) |
| المصدر: | Digital.CSIC. Repositorio Institucional del CSIC instname Addi. Archivo Digital para la Docencia y la Investigación Addi: Archivo Digital para la Docencia y la Investigación Universidad del País Vasco Physical Review Research Physical review research 3 (2021): 023131-1–023131-13. doi:10.1103/PhysRevResearch.3.023131 info:cnr-pdr/source/autori:Hijano A., Ili? S., Rouco M., González-Orellana C., Ilyn M., Rogero C., Virtanen P., Heikkilä T. T., Khorshidian S., Spies M., Ligato N., Giazotto F., Strambini E., Sebastián Bergeret F./titolo:Coexistence of superconductivity and spin-splitting fields in superconductor%2Fferromagnetic insulator bilayers of arbitrary thickness/doi:10.1103%2FPhysRevResearch.3.023131/rivista:Physical review research/anno:2021/pagina_da:023131-1/pagina_a:023131-13/intervallo_pagine:023131-1–023131-13/volume:3 |
| بيانات النشر: | arXiv, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | suprajohtavuus, nanoelektroniikka, Condensed Matter - Superconductivity, European research, Odd Triplet Superconductivity, FOS: Physical sciences, equation, 02 engineering and technology, Public administration, 021001 nanoscience & nanotechnology, 01 natural sciences, 3. Good health, suprajohteet, Superconductivity (cond-mat.supr-con), Spin splitting, Political science, Condensed Matter::Superconductivity, 0103 physical sciences, transport, 010306 general physics, 0210 nano-technology, EuS |
| الوصف: | Ferromagnetic insulators (FI) can induce a strong exchange field in an adjacent superconductor (S) via the magnetic proximity effect. This manifests as spin splitting of the BCS density of states of the superconductor, an important ingredient for numerous superconducting spintronics applications and the realization of Majorana fermions. A crucial parameter that determines the magnitude of the induced spin splitting in FI/S bilayers is the thickness of the S layer d: In very thin samples, the superconductivity is suppressed by the strong magnetism. By contrast, in very thick samples, the spin splitting is absent at distances away from the interface. In this work, we calculate the density of states and critical exchange field of FI/S bilayers of arbitrary thickness. From here, we determine the range of parameters of interest for applications, where the exchange field and superconductivity coexist. We show that for d>3.0ξs, the paramagnetic phase transition is always of the second order, in contrast to the first-order transition in thinner samples at low temperatures. Here ξs is the superconducting coherence length. Finally, we compare our theory with the tunneling spectroscopy measurements in several EuS/Al/AlOx/Al samples. If the Al film in contact with the EuS is thinner than a certain critical value, we do not observe superconductivity, whereas, in thicker samples, we find evidence of a first-order phase transition induced by an external field. The complete transition is preceded by a regime in which normal and superconducting regions coexist. We attribute this mixed phase to inhomogeneities of the Al film thickness and the presence of superparamagnetic grains at the EuS/Al interface with different switching fields. The steplike evolution of the tunnel-barrier magnetoresistance supports this assumption. Our results demonstrate on the one hand, the important role of the S layer thickness, which is particularly relevant for the fabrication of high-quality samples suitable for applications. On the other hand, the agreement between theory and experiment demonstrates the accuracy of our theory, which, originally developed for homogeneous situations, is generalized to highly inhomogeneous systems. F.S.B. acknowledges funding by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) (Project FIS2017-82804-P). T.T.H. acknowledges funding from the Academy of Finland (Project number 317118). A.H. acknowledges funding by the Department of Education of the Basque Government (Ikasiker grant). C.G.-O. acknowledges funding of the Ph.D. fellowship from MPC foundation. S.K. acknowledges for the fellowship of the ICTP Program for Training and Research in Italian laboratories, Trieste, Italy. C.R. acknowledges support from Gobierno Vasco (Grant No. IT 1255-19). F.G. acknowledges the European Research Council under the EU’s Horizon 2020 Grant Agreement No. 899315-TERASEC for partial financial support. We acknowledge funding from EU’s Horizon 2020 research and innovation program under Grant Agreement No. 800923 (SUPERTED). |
| وصف الملف: | application/pdf; fulltext |
| DOI: | 10.48550/arxiv.2012.15549 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::85f831ec6433763eff9773f56dc37ba1 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....85f831ec6433763eff9773f56dc37ba1 |
| قاعدة البيانات: | OpenAIRE |
| DOI: | 10.48550/arxiv.2012.15549 |
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