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

Abstract

We systematically investigate the crystal structure, magneto-optical properties, magnetization, and magnetotransport properties of a new ferromagnetic semiconductor $(\mathrm{G}{\mathrm{a}}_{1\ensuremath{-}x},\mathrm{F}{\mathrm{e}}_{x})\mathrm{Sb}$ grown by low-temperature molecular beam epitaxy. Crystal structure analyses by x-ray diffraction, scanning transmission microscopy, and transmission electron diffraction indicate that the $(\mathrm{G}{\mathrm{a}}_{1\ensuremath{-}x},\mathrm{F}{\mathrm{e}}_{x})\mathrm{Sb}$ thin films maintain the zinc-blende crystal structure up to $x=20%$. We carried out the characterizations of the magnetic properties of the $(\mathrm{G}{\mathrm{a}}_{1\ensuremath{-}x},\mathrm{F}{\mathrm{e}}_{x})\mathrm{Sb}$ thin films by various methods, including magnetic circular dichroism spectroscopy, anomalous Hall effect, and superconducting quantum interference device magnetometry, and found that $(\mathrm{Ga},\mathrm{Fe})\mathrm{Sb}$ is an intrinsic ferromagnetic semiconductor without any second-phase precipitations. The Curie temperature ${T}_{\mathrm{C}}$ of $(\mathrm{G}{\mathrm{a}}_{1\ensuremath{-}x},\mathrm{F}{\mathrm{e}}_{x})\mathrm{Sb}$ depends on $x$ and hole concentration, as in the case of hole-induced ferromagnetism. The highest ${T}_{\mathrm{C}}$ reaches 230 K at $x=20%$, which is the highest value so far reported in III-V based ferromagnetic semiconductors.