Magnetic and transport properties of MnGeP₂ films grown on GaAs(001) by molecular beam epitaxy

MnGeP₂ films were grown on undoped GaAs(001) substrates by molecular beam epitaxy. X-ray diffraction analysis reveals a film peak at 66.21°, corresponding to a c-axis of 1.128 nm for the chalcopyrite structure. Superconducting quantum interference device magnetic measurements show ferromagnetic order in the film with a transition temperature around 325 K and hysteresis loop measurements yield with coercive fields of about 1600 Oe and 210 Oe at 250 K and 300 K, respectively. The transport measurements exhibit nonmetallic behavior with p-type carriers and a carrier density increasing with temperature. The anomalous Hall effect (AHE) is observed in the film indicating spin polarized carriers. At low temperatures, the anomalous Hall resistance has a negative sign and decreases in magnitude with increasing temperature, changing sign around 150 K. It then increases with temperature, reaching a maximum around 250 K.