Preparation and properties of new magnetic recording media

在环形等离子体（TP）溅射方法中，对高电离等离子体中产生的高能粒子的行为进行了详细的研究。研究了这些高能粒子对NdFeB复合薄膜结构和性能的影响。本文还讨论了NdFeB薄膜作为新型磁记录介质的有效性。Ar气用作溅射气体。在靶后贴附永磁体的情况下，在低Ar气压下施加的电压低于350 V。在0.19 μ m/min的高速率和60 ℃的低衬底温度下沉积了NdFeB薄膜。利用飞行时间法研究了NdFeB平面环形靶中中性粒子的种类和动能。从飞行时间谱中发现，仅观察到从等离子体发射的光子。这说明TP溅射法中高能中性粒子没有轰击到基体上，对薄膜的结构和性能没有直接影响，薄膜既有晶态结构，也有非晶态结构，这与薄膜成分有关。易磁化方向垂直于薄膜平面。饱和磁化强度和矫顽力分别约为1000 emu/cc和1.5 kOe。这种薄膜对于使用垂直磁记录介质可能是非常有用的。

In the toroidal plasma (TP) sputtering method, the behavior of the high energy particles produced in the highly ionized plasma has been investigated in detail. The dependence of the structure and properties of NdFeB composite films on these high energy particles has been studied. The effectiveness of the NdFeB films as the novel magnetic recording media has also been discussed.Sputtering was performed by using a Fe planar ring target of iron with a purity of 99.9 %. Ar gas was used as a sputtering gas. In the case of the permanent magnet attached behind the target, the applied voltage was lower to 350 V at low Ar gas pressure.NdFeB films have been deposited at high rate of 0.19 mum/min and low substrate temperature of 60ﾟC. The target utilization efficiency in surface was about 90 %.The time-of-flight method has been used to investigate the kind and kinetic energy of neutral particles ejected from the NdFeB planar ring target. It has been found from the time- of-flight spectra that the photons emitted from the plasma was only observed. This suggests that in TP sputtering method, the neutral particles with high energy were not bombarded to the substrates and have not direct affects on the structure and properties of as-deposited films.The NdFeB films have both crystal and amorphous structures dependent of film composition. The direction of the easy magnetization is normal to the film plane. The saturation magnetization and the coercivity were about 1000 emu/cc and 1.5 kOe, respectively. This film may be very useful for using the perpendicular magnetic recording media.