Tunneling magnetoresistance in devices based on epitaxial NiMnSb with uniaxial anisotropy

TL;DR

This paper reports on the fabrication and characterization of tunnel magnetoresistance (TMR) junctions using epitaxial NiMnSb, demonstrating significant TMR ratios at room temperature and low temperature, with anisotropic switching properties suitable for sensor applications.

Contribution

It introduces a new TMR device based on epitaxial NiMnSb with uniaxial anisotropy, showing enhanced TMR ratios and anisotropic switching behavior.

Findings

TMR ratio of 8.7% at room temperature

TMR ratio of 14.7% at 4.2K

Uniaxial anisotropy affects switching characteristics

Abstract

We demonstrate tunnel magnetoresistance (TMR) junctions based on a tri layer system consisting of an epitaxial NiMnSb, aluminum oxide and CoFe tri layer. The junctions show a tunnelling magnetoresistance of Delta R/R of 8.7% at room temperature which increases to 14.7% at 4.2K. The layers show clear separate switching and a small ferromagnetic coupling. A uniaxial in plane anisotropy in the NiMnSb layer leads to different switching characteristics depending on the direction in which the magnetic field is applied, an effect which can be used for sensor applications.