Very high Curie temperature (470–530 K) in (Ga,Fe)Sb ferromagnetic semiconductor grown by step-flow mode on vicinal GaAs substrates

Narrow-gap Fe-doped III–V ferromagnetic semiconductors (FMSs), such as (In,Fe)Sb, (Ga,Fe)Sb, and (In,Fe)Sb, are promising candidates for active semiconductor spintronic devices thanks to their high Curie temperature (TC). In this work, we show that by growing (Ga,Fe)Sb thin films by the step-flow mode on vicinal GaAs (100) substrates with a high off-angle of 10°, we can achieve high-quality (Ga0.76,Fe0.24)Sb FMS with TC as high as 470–530 K, which are the highest TC reported so far for FMSs. The magnetic moment of Fe atoms in our sample reaches 4.5 μB/atom, which is close to the ideal magnetic moment of substitutional Fe3+ atoms (5 μB/atom) in a zinc blende crystal structure, and is twice that of α-Fe metal. Our work establishes a growth technique of very high TC FMSs for room-temperature semiconductor spintronic devices.