Magnetic properties of <i>n</i>-GaMnN thin films

TLDR

GaMnN thin films were synthesized by gas‑source molecular‑beam epitaxy with Mn concentrations ranging from 3 % to 12 % at. The films exhibited no secondary phase, were n‑type, and displayed room‑temperature ferromagnetism with a Curie temperature above 320 K, with 3 % Mn showing the strongest ordering per Mn atom.

Abstract

GaMnN thin films were synthesized using gas-source molecular-beam epitaxy. Mn concentrations between 3 and 12 at. % were investigated. No evidence of second-phase formation was observed by powder x-ray diffraction or high-resolution cross section transmission electron microscopy in films with 9% or less Mn. The films were n type as determined by capacitance–voltage or Hall analysis. Magnetic characterization performed using a squid magnetometer showed evidence of ferromagnetic ordering at room temperature for all samples. In agreement with theoretical predictions, material with 3% Mn showed the highest degree of ordering per Mn atom. At 320 K, the samples show a nonzero magnetization indicating a TC above room temperature.