Optimization of reactively sputtered Mn3GaN films based on resistivity measurements

TL;DR

This study demonstrates how low-temperature resistivity measurements can optimize the nitrogen content in Mn3GaN films produced by reactive sputtering, improving their structural and electronic properties for spintronics applications.

Contribution

The paper introduces a method to optimize nitrogen incorporation in Mn3GaN films via resistivity measurements, enhancing film quality for antiferromagnetic spintronics.

Findings

Optimized N2 flow yields films with metal-like resistivity behavior.

Resistivity measurements serve as an effective indicator of structural disorder.

Films show lattice contraction and high resistivity ratios under optimal conditions.

Abstract

Mn-based nitrides with antiperovskite structures have several properties that can be utilised for antiferromagnetic spintronics. Their magnetic properties depend on the structural quality, composition and doping of the cubic antiperovskite structure. Such nitride thin films are usually produced by reactive physical vapour deposition, where the deposition rate of N can only be controlled by the N2 gas flow. We show that the tuning of the N content can be optimised using low temperature resistivity measurements, which serve as an indicator of the degree of structural disorder. Several Mn3GaNx films were prepared by reactive magnetron sputtering under different N2 gas flows. Under optimised conditions, we obtain films that exhibit a metal-like temperature dependence, a vanishing logarithmic increase in resistivity towards zero, the highest resistivity ratio and a lattice contraction of 0.4 % along the growth direction when heated above that of the N\'eel temperature in agreement with the bulk samples.