Magnetotransport and magnetization properties of p-typeGa(1-x)Mn(x)As, a new III-V diluted magnetic semiconductor

A new III-V diluted magnetic semiconductor (DMS), Ga1-xMnxAs, can be grown by molecular beam epitaxy. When a low temperature growth procedure is followed, homogeneous material of excellent crystal quality with Mn concentrations up to x similar to 9% can be grown. Hole transport in these compounds is strongly affected by the antiferromagnetic exchange interaction between holes and Mn 3d spins. At a critical temperature T-c, with a value of around 50 K for Mn concentrations of 3-5%, magnetic long-range order of Mn-hole complexes induces a paramagnetic-ferromagnetic transition. Above T-c, it is shown that transport behaviour on both sides of the metal-insulator transition can be observed. Below T-c, due to the rising spontaneous magnetization, carrier mobility increases and the relative position of the Fermi level towards the mobility edge changes. Also, a negative magnetoresistance is measured.