Room temperature ferromagnetic properties of transition metal implanted Al0.35Ga0.65N

A nominally undoped MBE-grown Al0.35Ga0.65N thin film was implanted with Cr, Mn, and Ni with an energy of 200 keV to a dose of 5 x 1016 cm(-2) for Cr and Mn and to a dose of 3 x 1016 cm(-2) for Ni. The magnetic properties of these samples were measured using a superconducting quantum interference device (SQUID) magnetometer. The Cr-implanted Al0.35Ga0.65N annealed at 750 degrees C has a coercive field (H-C) of 178 Oe at 300 K, and field-cooled (FC) and zero-field-cooled (ZFC) magnetization measurements show evidence of ferromagnetism in this sample with an estimated Curie temperature of around 350 K. The Mn-implanted sample has an H-C of 180 Oe at 300 K after annealing at 750 degrees C for 5 min, which indicates a dominant ferromagnetic phase. The Ni-implanted Al0.35Ga0.65N produces clear ferromagnetic hysteresis at temperatures up to 350 K. FC-ZFC magnetization separation suggests the true presence of ferromagnetism in this material. (c) 2006 Published by Elsevier B.V.