Spin pumping in d-wave superconductor-ferromagnet hybrids

Article

关键词: QUASI-PARTICLES;    ANDREEV REFLECTION;    CHARGE SEPARATION;    GAP;    IMBALANCE;    SYMMETRY;    STATES;   

DOI  :  10.1103/PhysRevB.104.144428

来源: SCIE

【 摘 要 】

Spin pumping across ferromagnet/superconductor (F/S) interfaces has attracted much attention lately, yet the focus has been mainly on s-wave superconductor based systems whereas (high-temperature) d-wave superconductors such as YBa2Cu3O7-d (YBCO) have received scarce attention despite their fundamental and technological interest. Here we use wideband ferromagnetic resonance to study spin-pumping effects in bilayers that combine a soft metallic Ni80Fe20 (Py) ferromagnet and YBCO. We evaluate the spin conductance in YBCO by analyzing the magnetization dynamics in Py. We find that the Gilbert damping exhibits a drastic drop as the heterostructures are cooled across the normal-superconducting transition and then, depending on the S/F interface morphology, either stays constant or shows a strong upturn. This unique behavior is explained considering quasiparticle density of states at the YBCO surface, and is a direct consequence of zero-gap nodes for particular directions in the momentum space. Besides showing the fingerprint of d-wave superconductivity in spin pumping, our results demonstrate the potential of high-temperature superconductors for fine tuning of the magnetization dynamics in ferromagnets using k-space degrees of freedom of d-wave/F interfaces.

【 授权许可】

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