Structural, morphological and magnetic properties of AlGaN thin films co-implanted with Cr and Sm ions

Cr and Sm co-implanted AlGaN (AlGaN:Cr:Sm) films have been fabricated by metal organic chemical vapor deposition, ion implantation and annealing. No secondary phase and metal-related peak can be detected within the detection limit of X-ray diffraction measurement. The Raman analysis demonstrated that the peak of E2 (H) phonon mode of sample B is much more narrow and sharp than that of sample A. The atomic force microscopy measurements indicated that the root mean square roughness for sample A and sample B were 2.26 and 1.07 nm, respectively. According to superconducting quantum interference device analysis, the AlGaN:Cr:Sm films exhibit room-temperature ferromagnetism and colossal magnetic moment effect. Moreover, the saturation magnetization of sample B is 9.75 μB/atom, which is much higher than that of sample A (1.86 μB/atom). Finally, the possible origin of the room-temperature ferromagnetism in AlGaN:Cr:Sm films was discussed.