Anomalous spin-pumping behavior of half-metallic ferromagnet/d-wave superconductor heterostructures

Fuente: arXiv
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Main Authors: Hassan, Hadi H., Carreira, Santiago J., Cabero, M., Martinet, F., Buzdin, Alexander, Santamaria, Jacobo, Villegas, Javier E.
Format: Preprint
Published: 2026
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author Hassan, Hadi H.
Carreira, Santiago J.
Cabero, M.
Martinet, F.
Buzdin, Alexander
Santamaria, Jacobo
Villegas, Javier E.
author_facet Hassan, Hadi H.
Carreira, Santiago J.
Cabero, M.
Martinet, F.
Buzdin, Alexander
Santamaria, Jacobo
Villegas, Javier E.
contents Spin-pumping experiments in superconductor/ferromagnet heterostructures, which probe spin-sinking by the superconductor, have revealed a variety of complex behaviors. Most studies have focused on conventional s-wave superconductors combined with metallic or insulating ferromagnets. Here, we study a d-wave superconductor paired with a half-metallic ferromagnet, in epitaxial YBa2Cu3O7-d/La0.7Sr0.3MnO3 heterostructures with two crystalline orientations: one in which YBCO is c-axis oriented, and the other in which YBCO grows along the (103) direction. Using ferromagnetic resonance (FMR), we probe the temperature-dependent Gilbert damping coefficient α. For (103) heterostructures, α(T) initially decreases below Tc, but then increases at lower temperatures, exceeding normal-state levels. This behavior can be understood in terms of the opening of the superconducting gap and spin transport via nodal quasiparticles, which dominate when the ab-plane of YBCO is exposed at the interface. In stark contrast, c-axis heterostructures exhibit a pronounced enhancement of α(T) below Tc, peaking at 0.65-0.7Tc before decaying. This anomaly suggests the dominance of interface-bound Andreev states, arising from a locally suppressed superconducting order parameter due to proximity effects with the half-metallic LSMO.
format Preprint
id arxiv_https___arxiv_org_abs_2605_12381
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Anomalous spin-pumping behavior of half-metallic ferromagnet/d-wave superconductor heterostructures
Hassan, Hadi H.
Carreira, Santiago J.
Cabero, M.
Martinet, F.
Buzdin, Alexander
Santamaria, Jacobo
Villegas, Javier E.
Superconductivity
Spin-pumping experiments in superconductor/ferromagnet heterostructures, which probe spin-sinking by the superconductor, have revealed a variety of complex behaviors. Most studies have focused on conventional s-wave superconductors combined with metallic or insulating ferromagnets. Here, we study a d-wave superconductor paired with a half-metallic ferromagnet, in epitaxial YBa2Cu3O7-d/La0.7Sr0.3MnO3 heterostructures with two crystalline orientations: one in which YBCO is c-axis oriented, and the other in which YBCO grows along the (103) direction. Using ferromagnetic resonance (FMR), we probe the temperature-dependent Gilbert damping coefficient α. For (103) heterostructures, α(T) initially decreases below Tc, but then increases at lower temperatures, exceeding normal-state levels. This behavior can be understood in terms of the opening of the superconducting gap and spin transport via nodal quasiparticles, which dominate when the ab-plane of YBCO is exposed at the interface. In stark contrast, c-axis heterostructures exhibit a pronounced enhancement of α(T) below Tc, peaking at 0.65-0.7Tc before decaying. This anomaly suggests the dominance of interface-bound Andreev states, arising from a locally suppressed superconducting order parameter due to proximity effects with the half-metallic LSMO.
title Anomalous spin-pumping behavior of half-metallic ferromagnet/d-wave superconductor heterostructures
topic Superconductivity
url https://arxiv.org/abs/2605.12381