Magnetic properties of metal Ni nanoparticles prepared by ion implantation in rutile TiO2 single crystals

64 keV Ni ion implantation of a dose of 1×1017cm-2 was performed at room temperature in rutile TiO2 single crystals in which metallic Ni nanoparticles formed directly. Transmission electron microscopy and a superconducting quantum interference device (SQUID) magnetometer were used to characterize the microstructure and magnetic properties of Ni nanoparticles in TiO2. Metal Ni nanopartilces with size ranging 3~18 nm was observed in the near surface of TiO2. A high-resolution electron microscopy (HREM) image indicated the Ni-implanted area had been entirely amorphized. Magnetic measurement indicated that the coercive force of Ni nanoparticles was about 16.8 kA·m-1 at 10 K, which was larger than that of bulk materials of Ni. The blocking temperature obtained from ZFC/FC curves was about 85