The study of structural, optical, and magnetic properties of undoped and p-type GaN implanted with Mn⁺ (10 at.%)

GaMnN and GaMnN:Mg layers were prepared using implantation of 10 at.% Mn ions into undoped GaN and p-type GaN:Mg epilayers, respectively. For PL measurements, the samples clearly showed Mn-related transitions indicating a good activation of Mn ions in the host epilayers. Both samples revealed that two precipitate phases of Ga_5.2Mn and Mn₃Ga coexist with the main crystalline phase of GaMnN. A clear hysteresis loop indicative of obvious ferromagnetism was observed for both samples, and the transition of ferromagnetism showed two kinds of behaviors; i.e., a rapid transition from GaMnN DMS phase at the lower temperature region (75-100 K) and a released transition from Ga_5.2Mn and Mn₃Ga phases at the higher temperature region (above 300 K). The transition point related to GaMnN DMS phase for Mg-codoped GaMnN (∼100 K) was observed to be higher than undoped GaMnN (∼75 K). This result is considered as resulting from the increase of ferromagnetic interaction rates due to codoping of Mg acceptors.