Growth and magnetic properties of Ge1-xMnx single crystals

Group IV ferromagnetic semiconductor, Ge1-xMnx large size crystals were grown by the Czochralski method in an Ar ambient. The magnetic atom, Mn, was systematically doped into Ge crystal from x = 0 to x = 0.176 and these compositions precisely were obtained by glow discharge spectroscopy. The increase of Mn concentration brought a new Ge8Mn11 phase in Ge matrix. The magnetizations increase greatly reach a maximum value at x = 0.113. The formation of Ge8Mn11 phase is responsible for a ferromagn etic phase between 150 K and 281 K. Especially, in the ferromagnetic phase, the maximum remanent magnetization at x = 0.113 was 0.483 emu/g, which is larger than other results. This feature can be used for some spin devices, because of a large magnetic moment in a low magnetic field.