Enhanced magnetoresistance in perpendicular magnetic tunneling junctions with MgAl2O4 barrier

TL;DR

This study demonstrates that using reactive RF sputtering with O2 in MgAl2O4-based perpendicular magnetic tunnel junctions significantly enhances their magnetic anisotropy and magnetoresistance, with potential for improved spintronic devices.

Contribution

It introduces a fabrication process for MgAl2O4 junctions that achieves high perpendicular magnetic anisotropy and magnetoresistance, surpassing MgO-based junctions.

Findings

Interfacial perpendicular magnetic anisotropy energy density of 2.25 mJ/m2

Magnetoresistance of 60% achieved

Vhalf bias voltage around 1V, higher than MgO junctions

Abstract

Perpendicular magnetic tunnel junction with MgAl2O4 barrier is investigated. It is found that reactive RF sputtering with O2 is essential to obtain strong perpendicular magnetic anisotropy and large tunneling magnetoresistance in MgAl2O4-based junctions. An interfacial perpendicular magnetic anisotropy energy density of 2.25 mJ/m2 is obtained for the samples annealed at 400C. An enhanced magnetoresistance of 60% has also been achieved. The Vhalf, bias voltage at which tunneling magnetoresistance drops to half of the zero-bias value, is found to be about 1V, which is substantially higher than that of MgO-based junctions.