Negative GMR Effect in current perpendicular-to-plane (Zn,Cr)Te/Cu/Co spin salves

TL;DR

This paper investigates the negative magnetoresistance effect in CPP spin valves with Cr-doped ZnTe and Co, revealing a strong temperature dependence explained by differences in spin scattering asymmetry and spin polarization.

Contribution

It demonstrates the occurrence of negative GMR in (Zn,Cr)Te/Cu/Co spin valves and explains it through DFT-calculated spin polarization differences.

Findings

Negative magnetoresistance observed at low temperatures.

Strong temperature dependence of the GMR effect.

Differences in spin polarization explain the negative GMR.

Abstract

Magnetic and transport properties are explored in the current perpendicular-to-plane (CPP) spin salves with Cr doped wide band gap semiconductor ZnTe as one of the ferromagnetic electrodes. A negative magnetoresistance is observed in these CPP spin valves at low temperature, with a strong temperature dependence. This effect can be explained by the large difference of spin scattering asymmetry coefficients in (Zn,Cr)Te and Cobalt, due to the very different spin polarizations of the two materials as revealed by the DFT calculation.