Anisotropic Magneto-Thermopower: the Contribution of Interband Relaxation

TL;DR

This paper investigates anisotropic magneto-thermopower in ferromagnetic junctions, revealing a new interface resistance contribution due to anisotropic scattering and highlighting interband s-d relaxation mechanisms through experimental measurements.

Contribution

It introduces a generalized two-channel model showing an interface resistance from anisotropic scattering and presents first measurements of anisotropic magnetothermopower in Ni nanowires.

Findings

Interface resistance contribution from anisotropic scattering

Thermopower expression derived and compared with GMR

Experimental evidence of interband s-d relaxation mechanisms

Abstract

Spin injection in metallic normal/ferromagnetic junctions is investigated taking into account the anisotropic magnetoresistance (AMR) occurring in the ferromagnetic layer. It is shown, on the basis of a generalized two channel model, that there is an interface resistance contribution due to anisotropic scattering, beyond spin accumulation and giant magnetoresistance (GMR). The corresponding expression of the thermopower is derived and compared with the expression for the thermopower produced by the GMR. First measurements of anisotropic magnetothermopower are presented in electrodeposited Ni nanowires contacted with Ni, Au and Cu. The results of this study show that while the giant magnetoresistance and corresponding thermopower demonstrates the role of spin-flip scattering, the observed anisotropic magnetothermopower indicates interband s-d relaxation mechanisms.