Preparation of ferromagnetic (In,Mn)As with a high Curie temperature of 90 K

The authors found high Curie temperatures of up to 90 K in annealed (In,Mn)As epilayers grown by molecular beam epitaxy using a relatively high V/III beam flux ratio. Magnetization data suggest that increasing the As beam flux results in an increase in the effective Mn content, and the carrier transport data indicate an increase in the hole concentration from a 10(19) to 10(20) cm(-3) range with low-temperature annealing after growth. The highest Curie temperature was obtained in lattice matched (In,Mn)As/Al(As,Sb) samples. Both Hall effect and magneto-optical polar Kerr rotation measurements confirm that the high Curie temperature is due to hole-mediated ferromagnetism.