Magnetic and electrical properties of the ZnGeAs 2 : Mn chalcopyrite

摘要: Doping of the ZnGeAs2 semiconductor with manganese has produced compositions spontaneous magnetization and high Curie temperatures up to 367 K for composition 3.5 wt% Mn. Their magnetic properties are characteristic spin glasses at T < T S fields H 11 kOe. In stronger fields, glass state transforms into a phase 4–5 times weaker than that be expected under ferromagnetic ordering all Mn ions. This is obviously singly-connected containing regions frustrated bonds. The have inclusions noninteracting clusters, because these low exhibit strong increase in M, dependence M(T) being described by Langevin function. Measurements electrical resistivity ρ Hall effect revealed that, 30 K, 1.5 wt % higher which makes superexchange dominant gives rise onset state. nonuniform distribution ions accounts existence isolated their ferromagnetism generated carrier-mediated exchange. As temperature increases still more, mobility occurs faster decrease concentration, thus promoting an enhancement exchange growth clusters size, = come contact. signifies transition from multiply-to phase, contains microregions