Magnetic and optical properties of the InCrN system

Abstract

Room-temperature ferromagnetic In1-x Crx N films with x ranging from 0. 0005 to 0.04 and antiferromagnetic CrN films have been grown by plasma-assisted molecular-beam epitaxy. Electron and x-ray-diffraction techniques could find no evidence for precipitates or phase segregation within the films. Ferromagnetism was observed in the In1-x Crx N layers over a wide range of Cr concentrations, with the magnitude of the ferromagnetism found to correlate with the background carrier concentration. Higher n -type carrier concentrations were found to lead enhanced ferromagnetism, with maximum saturation and remnant moments of 7 and 0.7 emu cm3, respectively. The addition of Cr to the InN matrix led to reduced photoluminescence intensity and a shift of the peak to higher energy. These observations along with a band-gap-like optical transmission feature at 0.7 eV suggest that CrN has an indirect gap of approximately 0.7 eV and a direct ? -valley gap greater than 1.2 eV.