Ferromagnetic semiconductor ZnGeAs2 {Mn} with a curie point of 367 K

Germanium zinc diarsenide crystals with various manganese fractions, (ZnGeMn)As2, were prepared by reacting high-purity powders of zinc diarsenide, germanium, arsenic, and manganese. The manganese solubility at temperatures near the ZnGeAs2 melting temperature was 3.5 wt % as determined by X-ray fluorescence analysis. The unit cell volume decreased with rising manganese concentration. Magnetization in fields up to 50 kOe, magnetic susceptibility, electrical resistance, and Hall constants were measured over wide temperature ranges. Manganese-doped samples had spontaneous magnetization and high Curie temperatures reaching 367 K. Their magnetic properties are characteristic of spin glasses in low magnetic fields. In higher fields, the spin state changed to spontaneous magnetization.