Impact of Boron doping to the tunneling magnetoresistance of Heusler alloy Co2FeAl

TL;DR

This study demonstrates that Boron doping in Co2FeAl Heusler alloy magnetic tunnel junctions enhances their structural, magnetic, and transport properties, notably increasing tunneling magnetoresistance and revealing memristive effects at low annealing temperatures.

Contribution

It introduces Boron doping as a method to improve the performance of Co2FeAl-based magnetic tunnel junctions, with detailed analysis of structural and magnetic enhancements.

Findings

Boron doping reduces interfacial roughness.

Enhanced tunneling magnetoresistance observed.

Memristive effects linked to impurities at low annealing temperatures.

Abstract

Heusler alloys based magnetic tunnel junctions can potentially provide high magnetoresistance, small damping and fast switching. Here junctions with Co2FeAl as a ferromagnetic electrode are fabricated by room temperature sputtering on Si/SiO2 substrates. The doping of Boron in Co2FeAl is found to have a large positive impact on the structural, magnetic and transport properties of the junctions, with a reduced interfacial roughness and substantial improved tunneling magnetoresistance. A two-level magnetoresistance is also observed in samples annealed at low temperature, which is believed to be related to the memristive effect of the tunnel barrier with impurities.