Phase-dependent heat transport through magnetic Josephson tunnel junctions

TL;DR

This paper investigates how phase, magnetization, and spin-filter effects influence heat transport in superconductor-ferromagnet Josephson junctions, revealing mechanisms to control thermal conductance and enhance magnetothermal resistance.

Contribution

It provides a comprehensive theoretical analysis of phase-dependent heat transport in S/F Josephson junctions with spin-filter barriers, including new insights into singlet and triplet contributions.

Findings

Heat current depends on phase difference, spin-filter efficiency, and magnetization orientation.

Non-collinear magnetizations contribute to heat transport via singlet and triplet components.

Spin-filtering can significantly increase the magnetothermal resistance ratio.

Abstract

We present an exhaustive study of the coherent heat transport through superconductor-ferromagnet(S-F) Josephson junctions including a spin-filter (I$_{sf}$) tunneling barrier. By using the quasiclassical Keldysh Green's function technique we derive a general expression for the heat current flowing through a S/F/I$_{sf}$/F/S junction and analyze the dependence of the thermal conductance on the spin-filter efficiency, the phase difference between the superconductors and the magnetization direction of the ferromagnetic layers. In the case of non-collinear magnetizations we show explicitly the contributions to the heat current stemming from the singlet and triplet components of the superconducting condensate. We also demonstrate that the magnetothermal resistance ratio of a S/F/I$_{sf}$/F/S heat valve can be increased by the spin-filter effect under suitable conditions.