Unconventional carrier-mediated ferromagnetism above room temperature in ion-implanted (Ga, Mn)P:C -: art. no. 107203

Ion implantation of Mn ions into hole-doped GaP has been used to induce ferromagnetic behavior above room temperature for optimized Mn concentrations near 3 at. %. The magnetism is suppressed when the Mn dose is increased or decreased away from the 3 at. % value, or when n-type GaP substrates are used. At low temperatures the saturated moment is on the order of 1 Bohr magneton, and the spin wave stiffness inferred from the Bloch-law T-3/2 dependence of the magnetization provides an estimate T-c=385 K of the Curie temperature that exceeds the experimental value, T-c=270 K. The presence of ferromagnetic clusters and hysteresis to temperatures of at least 330 K is attributed to disorder and proximity to a metal-insulating transition.