Dependence of magnetic properties on the growth conditions of MnGaN grown by rf N plasma molecular beam epitaxy

Abstract MnGaN has been grown by radio frequency N plasma‐assisted molecular beam epitaxy. MnGaN samples were grown on MOCVD GaN(0001)/sapphire(0001) at substrate temperature of 550 °C under different Ga/N flux ratios leading to 4 different growth regimes: N‐rich, slight metal‐rich, metal‐rich, and Ga‐rich. It is found that in the case of MnGaN, Mn incorporation and hence magnetic properties clearly depend on the growth conditions. Briefly, it is found that the N‐rich conditions give a sample with much larger magnetization compared to the other samples. Slight metal‐rich and metal‐rich grown samples have very little magnetization. Finally, Ga‐rich grown samples have intermediate level of magnetization. Possible origins of the magnetization are discussed. Ga‐rich magnetization is attributed to accumulates, but N‐rich magnetization is attributed to carrier‐mediated ferromagnetism and/or ferromagnetism due to clusters. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)