A1 Journal article (refereed)
Nonlinear spin torque, pumping, and cooling in superconductor/ferromagnet systems (2020)

Ojajärvi, R., Manninen, J., Heikkilä, T. T., & Virtanen, P. (2020). Nonlinear spin torque, pumping, and cooling in superconductor/ferromagnet systems. Physical Review B, 101(11), Article 115406. https://doi.org/10.1103/PhysRevB.101.115406

JYU authors or editors

Publication details

All authors or editors: Ojajärvi, Risto; Manninen, Juuso; Heikkilä, Tero T.; Virtanen, Pauli

Journal or series: Physical Review B

ISSN: 2469-9950

eISSN: 2469-9969

Publication year: 2020

Volume: 101

Issue number: 11

Article number: 115406

Publisher: American Physical Society

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1103/PhysRevB.101.115406

Publication open access: Not open

Publication channel open access: 

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/68327

Publication is parallel published: http://urn.fi/URN:NBN:fi:aalto-202003132498

Web address of parallel published publication (pre-print): https://arxiv.org/abs/1907.00424

Abstract

We study the effects of the coupling between magnetization dynamics and the electronic degrees of freedom in a heterostructure of a metallic nanomagnet with dynamic magnetization coupled with a superconductor containing a steady spin-splitting field. We predict how this system exhibits a nonlinear spin torque, which can be driven either with a temperature difference or a voltage across the interface. We generalize this notion to arbitrary magnetization precession by deriving a Keldysh action for the interface, describing the coupled charge, heat, and spin transport in the presence of a precessing magnetization. We characterize the effect of superconductivity on the precession damping and the antidamping torques. We also predict the full nonlinear characteristic of the Onsager counterparts of the torque, showing up via pumped charge and heat currents. For the latter, we predict a spin-pumping cooling effect, where the magnetization dynamics can cool either the nanomagnet or the superconductor.

Keywords: superconductivity; superconductors; magnets; nanoelectronics

Free keywords: spin caloritronics; spin transfer torque

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Ministry reporting: Yes

Reporting Year: 2020

JUFO rating: 2