Ferromagnetic Transition in Ge1-xMnxTe Layers

Ferromagnetic transition temperature in thin layers of diluted magnetic (semimagnetic) semiconductor Ge1-xMnxTe was studied experimentally by SQUID magnetometry method and analyzed theoretically for a model Ising-type diluted magnetic. system with Ruderman-Kittel-Kasuya-Yosida indirect exchange interaction. The key features of the experimentally observed dependence of the Curie temperature on Mn content (x <= 0 12) and conducting hole concentration p = (1-10) x 10(21) cm(-3) were reproduced theoretically for realistic valence band and crystal lattice parameters of p-Ge1-xMnxTe taking into account short carrier mean free path encountered in this material and Ruderman-Kittel-Kasuva-Yosida mechanism with both delta-like and diffused character of spatial dependence of the exchange coupling between magnetic ions and free carriers.