离子注入金红石单晶生成的金属Ni纳米晶的磁学性能研究

Magnetic properties of metal Ni nanoparticles prepared by ion implantation in rutile TiO_2 single crystals

研究了能量为64 keV、注量1×1017 cm-2的Ni离子注入金红石TiO2单晶制备的植入金属纳米晶的微观结构和磁学性能.注入层的结构和磁学性能采用透射电子显微分析(TEM)和超导量子干涉磁强计(SQUID)进行分析.结果表明,金红石单晶中有尺寸为3～18 nm的金属Ni纳米晶生成,注入区域基体明显非晶化.10 K温度下金属Ni纳米晶的矫顽力约为16.8 kA·m-1,比Ni块材的矫顽力大.样品的零场冷却/有场冷却(ZFC/FC)曲线表明,金属Ni纳米晶的截止温度约为85 K.

64 keV Ni ion implantation of a dose of 1 × 1017 cm-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 K.