摘要
Magnetic, thermal and electrical properties of sputtered Co_(60)Fe_(20)B_(20) alloy films are investigated. An excellent linear relationship between the saturation magnetization per unit area and thickness is obtained in the as-deposited film with thickness ranging from 10 to 100 nm. For the as-deposited films a high effective saturation magnetization of 793.7 ± 42.9 emu cm_(-3) is derived from the fitting. An in-plane uniaxial magnetic anisotropy of ~10~4 erg cm^(-3)in magnitude is revealed by angular dependent magnetic measurements.A fourfold cubic magnetic anisotropy is found to develop with annealing, in line with the improvement of the crystalline structure in the film confirmed by X-ray diffraction measurements. Thermomagnetic measurements reveal a considerable variation of the saturation magnetization with temperature arising from the competition of the crystallization and the temperature dependent ferromagnetic behavior of the alloy film. Pronounced changes in electrical resistivity with temperature were observed in the alloy film,in accompany with the structural change. The activation barrier for crystallization was determined to be 1.43 eV from the electrical measurements with variable heating rates,showing a good thermal stability of the alloy film.
本文研究了溅射制备的三明治结构Ta/Co_(60)Fe_(20)B_(20)/MgO合金薄膜的磁、热、电及晶化动力学特性.10–100 nm厚度的沉积态合金薄膜单位面积磁化强度和厚度呈现了极好的线性相关性,由此拟合出沉积态合金薄膜有效饱和磁化强度高达793.7 emu cm(-3).转角磁测量揭示了沉积态的合金薄膜具有面内磁单轴各向异性,其大小为10~4 erg cm^(-3)数量级.发现4重对称的立方结构磁各向异性随着退火温度升高而增大,这与XRD衍射测量的样品结构的变化一致.热磁曲线揭示了合金薄膜随温度有相当大变动的饱和磁化强度,这来源于合金晶化与温度相关的铁磁行为的竞争作用.伴随结构变化,观察到明显的合金薄膜电阻随温度的变化.通过变速率加热电阻测量得到晶化激活能为1.43 eV,表明该合金材料具有很好的热稳定性.
基金
supported by the Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University(ZQN-YX107)
Research Start-up Funding for High-level Talents Project Sponsored by Huaqiao University(13BS401)
