Triplet supercurrents in lateral Josephson junctions with a half-metallic ferromagnet

Fuente: arXiv
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Autores principales: Junxiang, Yao, Fermin, Remko, Cabero, Mariona, Lahabi, Kaveh, Aarts, Jan
Formato: Preprint
Publicado: 2023
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author Junxiang, Yao
Fermin, Remko
Cabero, Mariona
Lahabi, Kaveh
Aarts, Jan
author_facet Junxiang, Yao
Fermin, Remko
Cabero, Mariona
Lahabi, Kaveh
Aarts, Jan
contents In the area of superconducting spintronics, spin triplet supercurrents in half-metallic ferromagnets (HMFs) could yield dissipationless spin transport over large distances, and high current density. Promising among the HMFs is the perovskite oxide La0.7Sr0.3MnO3 (LSMO), and recent studies in combination with the high-Tc superconductor YBa2Cu3O7, or the conventional superconductor NbTi, showed long range effects. Here we focus on two issues that as yet received less attention: the value of the critical current in the HMF in the limit of a very small electrode distance (20 nm), and the nature of the spin triplet generator. We use lateral junctions shaped as bar, square, and disk, and find high supercurrent densities, of order 10^11 A/m2, pointing to an efficient triplet generation mechanism. This is surprising in the sense that no magnetic inhomogeneity is purposely built in, as is done in conventional metal triplet junctions. Furthermore, from the magnetic field dependence of the critical current interference patterns we find a uniform supercurrent distribution in bar-shaped devices, but one more constricted to the rim in disk devices, which is an expected consequence of the geometry. We also analyze the temperature dependence of the critical current and find the quadratic dependence that was predicted in the limit of small junction lengths. From studying the NbTi/LSMO interface with scanning electron transmission microscopy, we conclude that the magnetic inhomogeneity required for triplet generation resides in the LSMO layer adjacent to the interface.
format Preprint
id arxiv_https___arxiv_org_abs_2303_13922
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Triplet supercurrents in lateral Josephson junctions with a half-metallic ferromagnet
Junxiang, Yao
Fermin, Remko
Cabero, Mariona
Lahabi, Kaveh
Aarts, Jan
Superconductivity
In the area of superconducting spintronics, spin triplet supercurrents in half-metallic ferromagnets (HMFs) could yield dissipationless spin transport over large distances, and high current density. Promising among the HMFs is the perovskite oxide La0.7Sr0.3MnO3 (LSMO), and recent studies in combination with the high-Tc superconductor YBa2Cu3O7, or the conventional superconductor NbTi, showed long range effects. Here we focus on two issues that as yet received less attention: the value of the critical current in the HMF in the limit of a very small electrode distance (20 nm), and the nature of the spin triplet generator. We use lateral junctions shaped as bar, square, and disk, and find high supercurrent densities, of order 10^11 A/m2, pointing to an efficient triplet generation mechanism. This is surprising in the sense that no magnetic inhomogeneity is purposely built in, as is done in conventional metal triplet junctions. Furthermore, from the magnetic field dependence of the critical current interference patterns we find a uniform supercurrent distribution in bar-shaped devices, but one more constricted to the rim in disk devices, which is an expected consequence of the geometry. We also analyze the temperature dependence of the critical current and find the quadratic dependence that was predicted in the limit of small junction lengths. From studying the NbTi/LSMO interface with scanning electron transmission microscopy, we conclude that the magnetic inhomogeneity required for triplet generation resides in the LSMO layer adjacent to the interface.
title Triplet supercurrents in lateral Josephson junctions with a half-metallic ferromagnet
topic Superconductivity
url https://arxiv.org/abs/2303.13922