title: Unconventional carrier-mediated ferromagnetism above room temperature in ion-implanted (Ga, Mn)P:C.
abstract: 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.
authors.affiliation: Department of Physics, University of Florida, Gainesville 32611-8440, USA.
authors.forename: N
authors.initials: N
authors.lastname: Theodoropoulou
authors.forename: A F
authors.initials: AF
authors.lastname: Hebard
authors.forename: M E
authors.initials: ME
authors.lastname: Overberg
authors.forename: C R
authors.initials: CR
authors.lastname: Abernathy
authors.forename: S J
authors.initials: SJ
authors.lastname: Pearton
authors.forename: S N G
authors.initials: SN
authors.lastname: Chu
authors.forename: R G
authors.initials: RG
authors.lastname: Wilson