Magnetic properties and intrinsic ferromagnetism in (Ga, Fe)Sb ferromagnetic semiconductors

We systematically investigate the crystal structure, magneto-optical properties, magnetization, and magnetotransport properties of a new ferromagnetic semiconductor (Ga1-x, Fe-x)Sb grown by low-temperature molecular beam epitaxy. Crystal structure analyses by x-ray diffraction, scanning transmission microscopy, and transmission electron diffraction indicate that the (Ga1-x, Fe-x)Sb thin films maintain the zinc-blende crystal structure up to x = 20%. We carried out the characterizations of the magnetic properties of the (Ga1-x, Fe-x) Sb thin films by various methods, including magnetic circular dichroism spectroscopy, anomalous Hall effect, and superconducting quantum interference device magnetometry, and found that (Ga,Fe)Sb is an intrinsic ferromagnetic semiconductor without any second-phase precipitations. The Curie temperature TC of (Ga1-x, Fe-x)Sb depends on x and hole concentration, as in the case of hole-induced ferromagnetism. The highest T-C reaches 230 K at x = 20%, which is the highest value so far reported in III-V based ferromagnetic semiconductors.