Ferromagnetic properties of nickel implanted Al0.35Ga0.65N

초록

Magnetic characterization studies of Ni-implanted Al0.35Ga0.65N have been made for various magnetic fields and sample temperatures by using a superconducting quantum interference device (SQUID). Ni ions were implanted at 200 keV to a dose of 3 x 1016 cm(-2) at room temperature. The material was found to show clear signs of ferromagnetism after annealing between 675 and 775 degrees C for 5 min. The ferromagnetic property persisted above room temperature, and a coercive field width of 118 Oe and a remanent field of 16 % of the saturation magnetization of 2.6 x 10(-5) emu were obtained at 300 K after annealing at an optimum annealing temperature of around 750 degrees C. This ferromagnetic property was also confirmed with field-cooled and zero-field-cooled magnetization measurements, and the Curie temperature was estimated to be around 350 K. Cathodoluminescence and X-ray diffraction (XRD) measurements showed that the significant implantation-related damage was recovered after annealing at 750 degrees C, indicating a good Ni incorporation in the Al0.35Ga0.65N. Furthermore, the XRD measurements also showed no indication of secondary phase formation or Ni clusters, which implies that we had observed a dilute ferromagnetic semiconductor behavior.

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