Giant Magneto-Seebeck Effect in Spin Valves

TL;DR

This paper reports the observation of a giant magneto-Seebeck effect in spin valves, revealing a significant change in thermoelectric response depending on magnetic configuration, with potential applications in sensing and spin polarization measurement.

Contribution

It introduces the first experimental observation of the giant magneto-Seebeck effect in spin valves and explains its origin using a spin-dependent thermoelectric model.

Findings

GMS ratio reached -9% in experiments.

A simple two-channel model predicted -11% GMS.

GMS can be used for magnetic and temperature sensing.

Abstract

Giant magneto-Seebeck (GMS) effect was observed in Co/Cu/Co and NiFe/Cu/Co spin valves. Their Seebeck coefficients in parallel state was larger than that in antiparallel state, and GMS ratio defined as (SAP-SP)/SP could reach -9% in our case. The GMS originated not only from trivial giant magnetoresistance but also from spin current generated due to spin polarized thermoelectric conductivity in ferromagnetic materials and subsequent modulation of the spin current by spin configurations in spin valves. Simple Mott two-channel model reproduced a -11% GMS for the Co/Cu/Co spin valves, qualitatively consistent with our observations. The GMS effect could be applied simultaneously sensing temperature gradient and magnetic field and also be possibly applied to determine spin polarization of thermoelectric conductivity and Seebeck coefficient in ferromagnetic thin films.