Mn impurity inGa1−xMnxAsepilayers

Abstract

Electron paramagnetic resonance was measured in ${\mathrm{Ga}}_{1-x}{\mathrm{Mn}}_x\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ epilayers with $0.002<~x<~\mathrm{0.01.}$ Data were taken as a function of magnetic field orientation at low temperatures. The observed spectra were attributed to ionized Mn acceptor $A^{-}.$ No neutral Mn acceptor centers were detected. The observed anisotropy of $A^{-}$ is interpreted in terms of sizable demagnetizing fields resulting from ferromagnetic coupling between Mn ions.