Enhancement of the magnetic properties in (Ga _1-xMn _x) N thin films due to Mn-delta doping

The effects of Mn delta-doping on the magnetic properties of (Ga1-x Mnx) N thin films grown on GaN buffer layers by molecular-beam epitaxy were studied. The magnetization curve as a function of the magnetic field as 5 K indicated that ferromagnetisms existed in the Mn delta-doped (Ga1-x Mnx) N and (Ga1-x Mnx) N thin films and that the magnetization in the Mn delta-doped (Ga1-x Mnx) N thin film was significantly enhanced. The magnetization curve as a function of the temperature showed that the Curie temperature of the Mn delta-doped (Ga1-x Mnx) N thin film was estimated to be above room temperature. The increase of the magnetization in the Mn delta-doped (Ga1-x Mnx) N thin film in comparison with that in the (Ga1-x Mnx) N thin film was attributed to the enhancement of the carrier-mediated ferromagnetism due to increased hole concentrations. The theoretical results showed that Ga vacancies near the Mn delta-doping layer were likely to cause p -type conductance, indicating that the enhancement of the magnetic properties in (Ga1-x Mnx) N thin films originated from Mn delta doping.