Single Ferromagnetic Domain Observed in Single Core-shell GaN/GaN:Mn Micro-wire Grown by Metalorganic Chemical Vapor Deposition

Spontaneously self-organized growth of core-shell GaN/GaN:Mn micro-wires were obtained by metalorganic chemical vapor deposition (MOCVD) without catalyst. The structure and magnetic properties of single core-shell GaN/GaN:Mn micro-wire were investigated. Mn atoms substituted for the Ga atoms without microprecipitates or clusters in the GaN:Mn shell layer. The magnetic hysteresis curve showed that the core-shell GaN/GaN:Mn micro-wires were ferromagnetic above room temperature. In addition, a single ferromagnetic domain was confirmed by magnetic force microscope (MFM) in the as-grown GaN:Mn shell layer without external magnetic field applied before, excluding secondary phases in GaN:Mn.