ZINC-BLEND MG1-XMNXTE - A NEW DILUTED MAGNETIC SEMICONDUCTOR SYSTEM

Molecular-beam epitaxy was successfully used to grow new diluted magne tic semiconductor Mg1-xMnxTe with zinc blende structure. Layers 3-5 mu m thick with Mg molar fraction ranging between 0 and 1 were grown on GaAs(100) 2 degrees off substrates from elemental sources. Layers with Mg content greater than 0.8 were not stable in air and decomposed wit h time. To avoid this, MgTe films were protected against hydration by CdTe cap layer. Under such protection they proved to be stable for sev eral weeks. X-ray diffraction measurements did not reveal any other cr ystallographic phases apart from cubic zinc blende phase and indicated a good crystallographic quality. Lattice parameters were determined b y high-resolution X-ray diffraction for the entire range of compositio ns. The energy gap variation with Mg molar fraction was studied by mag netic circular dichroism in reflectance configuration at T = 2 K. Meas urements of magnetic properties performed by SQUID magnetometry eviden ced formation of a spin-glass-like phase. The magnetic phase diagram T -c(x) is presented. (C) 1998 Elsevier Science B.V. All rights reserved .