Spin mediated magneto-electro-thermal transport behavior in Ni80Fe20/MgO/p-Si thin films

TL;DR

This study demonstrates that spin accumulation, induced by the spin-Hall effect, significantly influences electro-thermal transport in Ni80Fe20/MgO/p-Si thin films, revealing new insights into spin-mediated behavior in semiconductors.

Contribution

First experimental evidence of spin accumulation affecting electro-thermal transport in p-Si via the spin-Hall effect, highlighting a novel spin-mediated transport mechanism.

Findings

Spin accumulation alters phononic thermal transport in p-Si.

Inverted magnetoresistance switching observed at low temperatures.

Anomalous Hall resistance decreases with increasing current.

Abstract

In Si, spin-phonon interaction is the primary spin relaxation mechanism. At low temperatures, the absence of spin-phonon relaxation will lead to enhanced spin accumulation. Spin accumulation may change the electro-thermal transport within the material, and thus may serve as an investigative tool for characterizing spin-mediated behavior. Here we present the first experimental proof of spin accumulation induced electro-thermal transport behavior in a Pd (1 nm)/Ni80Fe20 (25 nm)/MgO (1 nm)/p-Si (2 um) specimen. The spin accumulation originates from the spin-Hall effect. The spin accumulation changes the phononic thermal transport in p-Si causing the observed magneto-electro-thermal transport behavior. We also observe the inverted switching behavior in magnetoresistance measurement at low temperatures in contrast to magnetic characterization, which is attributed to the canted spin states in p-Si due to spin accumulation. The spin accumulation is elucidated by current dependent anomalous Hall resistance measurement, which shows a decrease as the electric current is increased. This result may open a new paradigm in the field of spin-mediated transport behavior in semiconductor and semiconductor spintronics.