Magnetic properties of MnGeAsP films grown on GaAs (100) by molecular beam epitaxy

Magnetic MnGeAsP films with the nominal composition MnGe(As1-xPx)2 were grown on GaAs(100) by solid source molecular beam epitaxy. The films were grown keeping the Mn, Ge, and As fluxes constant while varying the P flux via its cell temperature. A streaky reflection high energy electron diffraction pattern with intensity variations along each reflection line was observed, suggesting small domain sizes in the films. The incorporation of P in the films was examined by x-ray photoelectron spectroscopy, and an increase of the P/As peak ratio was observed with increasing phosphorous cell temperature. Superconducting quantum interference device magnetic measurements revealed a clear change in the magnetic properties as phosphorous was introduced into the films. The coercive field decreases with increasing P/As ratio. The measured Curie temperatures were over 380 K for P/As ratios larger than 2, which is higher than that of a nominal MnGeAs2 and MnGeP2 film