III-V based magnetic(GaMnAs)/nonmagnetic(AlAs) semiconductor superlattices

III-V based magnetic (GaMnAs)/nonmagnetic(AlAs) semiconductor superlattices (SLs) have been grown by low-temperature molecular beam epitaxy, X-ray diffraction measurements show that the SLs have good crystalline quality and abrupt interfaces, The SLs having relatively wide (Ga,Mn)As layers (greater than or equal to 70 Angstrom) are found to be ferromagnetic at low temperatures, while the SLs with narrow (Ga,Mn)As layers (less than or equal to 50 Angstrom) are paramagnetic even at 2.0 K. Magneto-optic spectra have revealed that, due to the quantum confinement effect, the interband transition energy at Gamma is blue shifted with decreasing the thickness of the (Ga,Mn)As and some subbands are formed. (C) 1997 American Institute of Physics.