Control of Mn₃GaN Magnetism and Anomalous Hall Conductivity with N content

Antiperovskite Mn₃GaN is a metallic antiferromagnet whose frustrated non collinear spin configurations can generate spin Hall and anomalous Hall transport phenomena with potential spintronic applications. These properties can be tuned with N stoichiometry, which we pursue in epitaxial thin films with substate clamping to constrain the in-plane lattice constant. We use electronic transport combined with SQuID magnetometry to probe the magnetic properties. These data indicate that reducing the N gas fraction in the reactive deposition environment increases the Neel transition temperature, and induces an anomalous Hall signature and a low-temperature magnetic moment. Using this anomalous Hall signature, we generate a phase diagram summarizing the electronic properties as a function of N growth fraction. We discuss these results in the context of the microscopic magnetic structures.