1500-fold Tunneling Anisotropic Magnetoresistance in a (Ga,Mn)As stack

TL;DR

This paper reports a super-giant tunneling anisotropic magnetoresistance effect in a (Ga,Mn)As structure, driven by electronic structure dependence on magnetization orientation, with potential for advanced spintronic applications.

Contribution

The discovery of a super-giant tunneling anisotropic magnetoresistance effect in (Ga,Mn)As structures, highlighting a new mechanism based on electronic structure dependence on magnetization orientation.

Findings

1500-fold magnetoresistance observed

Both normal and inverted spin-valve signals

Large, non-hysteretic magnetoresistance at low bias and temperature

Abstract

We report the discovery of a super-giant tunneling anisotropic magnetoresistance in an epitaxially grown (Ga,Mn)As/GaAs/(Ga,Mn)As structure. The effect arises from a strong dependence of the electronic structure of ferromagnetic semiconductors on the magnetization orientation rather than from a parallel or antiparallel alignment of the contacts. The key novel spintronics features of this effect are: (i) both normal and inverted spin-valve like signals; (ii) a large non-hysteretic magnetoresistance for magnetic fields perpendicular to the interfaces; (iii) magnetization orientations for extremal resistance are, in general, not aligned with the magnetic easy and hard axis. (iv) Enormous amplification of the effect at low bias and temperatures.