GaMnN growth on GaAs (100) using a GaN single precursor via molecular beam epitaxy was undertaken. The grown layers revealed p-type conduction. It is confirmed that p-GaMnN reveals room temperature ferromagnetism with hysteresis loop having a coercivity of ∼100 Oe. The segregated phase showing a transition temperature of ∼200 K is assigned to Mn3GaN, and which enhances the conductivity of the surrounding GaMnN region. As a consequence, the GaMnN layer with segregation revealed an anomalous Hall effect at room temperature proving magnetotransport in GaMnN phase. The enhanced conductivity of GaMnN by the highly conductive second phase also revealed the importance of the role of the free carriers in the carrier-mediated ferromagnetism.

Hexagonal GaN thin films are deposited on Si(111) from diethylazidogallium methylhydrazine adduct in a high vacuum CVD system and at a relatively low deposition temperature. Characterization of the GaN thin films using double crystal XRD indicates an FWHM of 0.4. Pole figure and photoluminescence analysis produces results comparable to that of high‐quality undoped h‐GaN films. XPS analysis shows the atomic ratio of Ga/N to be 1:0.94. A CVD mechanism is proposed on the basis of GC‐MS analysis suggesting precursor decomposition via the protonation of the ethyl group.

Superconducting Hg-based cuprate thin films have been fabricated on (100) SrTiO3 substrate using rf sputtering and post-Hg-vapor annealing. These films are dominated by c-axis-oriented Hg-1223 phase as indicated by x-ray diffraction and SQUID measurements. Using four-probe technique, the Tc,onset was found to be 130–132 K and Jc was up to 8.5×104 A/cm2 at 77 K and zero field.

The effects of Mg codoping on the structural, electronic transport, and magnetic properties of GaMnN films are investigated. Mg was shown to compete with Mn for incorporation into the growing films at impingement, and to replace Mn. The partial replacement of Mn by Mg in GaMnN has resulted in an increase of conductivity of the region. The enhanced transport property due to the highly efficient dopant Mg resulted in a remarkable increase of the saturation magnetization, indicating an interaction between Mn and Mg for the carrier-mediated ferromagnetism. The increased carrier population by Mg codoping enabled a full mediation among the Mn atoms, and consequently, suppressed the paramagnetic rise in the temperature-dependent magnetization measurement.

GaMnN and Mg-codoped GaMnN films were grown in molecular beam epitaxy using a GaN single precursor. The structural, electrical, and magnetic properties were examined. The Mg-codoped GaMnN layers revealed room-temperature ferromagnetism. Codoping with Mg reduces the Mn incorporation, but increases the conductivity of the GaMnN films. At the same time, the saturation magnetization and coercivity have increased at room temperature. As this improvement was obtained with much reduced Mn concentration of ∼0.3%, the crucial role of the carriers for carrier-induced ferromagnetism in magnetic semiconductors is observed.