Dependence of ferromagnetic properties on phosphorus concentration in Ga1-xMnxAs1-yPy

A series of Ga1-xMnxAs1-yPy thin films grown on GaAs (100) substrates by molecular beam epitaxy were systematically investigated to establish the effect of phosphorous on structural and magnetic properties of the alloy. Detailed characterization of both as-grown and annealed samples by x-ray diffraction and magnetometry were carried out. Reciprocal space map scans confirmed that the quaternary alloy is fully strained by the substrate throughout its thickness. Magnetization measurements revealed a clear trend of decreasing Curie temperature with increasing P concentration, and revealed that the magnetic easy axis gradually turns from in-plane to out-to-plane orientation as P concentration increases.