Growth and characterization of insulating ferromagnetic semiconductor (Al,Fe)Sb

We investigate the crystal structure, transport, and magnetic properties of Fe-doped ferromagnetic semiconductor (Al1-x,Fe-x)Sb thin films up to x = 14% grown by molecular beam epitaxy. All the samples show p-type conduction at room temperature and insulating behavior at low temperature. The (Al1-x,Fe-x) Sb thin films with x <= 10% maintain the zinc blende crystal structure of the host material AlSb. The (Al1-x,Fe-x) Sb thin film with x = 10% shows intrinsic ferromagnetism with a Curie temperature (T-C) of 40K. In the (Al1-x,Fe-x) Sb thin film with x = 14%, a sudden drop of the hole mobility and T-C was observed, which may be due to the microscopic phase separation. The observation of ferromagnetism in (Al,Fe)Sb paves the way to realize a spin-filtering tunnel barrier that is compatible with well-established III-V semiconductor devices. (C) 2015 AIP Publishing LLC.