Carrier-mediated ferromagnetic ordering in Mn ion-implanted p+GaAs: C

Highly p-type GaAs:C was ion implanted with Mn at differing doses to produce Mn concentrations in the 1\char21{}5 at. % range. In comparison to LT-GaAs and ${n}^{+}\mathrm{GaAs}:\mathrm{Si}$ samples implanted under the same conditions, transport and magnetic properties show marked differences. Transport measurements show anomalies, consistent with observed magnetic properties and with epi-LT-(Ga,Mn)As, as well as the extraordinary Hall effect up to the observed magnetic ordering temperature ${(T}_{C}).$ Mn ion-implanted ${p}^{+}\mathrm{GaAs}:\mathrm{C}$ with as-grown carrier concentrations $g{10}^{20}{\mathrm{cm}}^{\ensuremath{-}3}$ show remanent magnetization up to 280 K.