Development of high-rate sputtering system for Ba-ferrite thin film rigid disk for ultra high density magnetic recording

为了发展一种新的高密度磁记录介质制造技术，建立了一套对靶溅射系统。在该系统中，即使使用厚的铁靶，也可以以高速率沉积铁磁薄膜。从我们以前的研究中发现，钡铁氧体薄膜可以在较高的衬底温度下制备。钡铁氧体薄膜虽然具有优良的磁记录性能，但不适合大规模生产。在本研究中，我们提出了一种制备高密度、高速率记录介质的新技术，即在室温下沉积钡铁氧体薄膜，并对其进行连续退火晶化。通过与传统直流磁控溅射系统和对靶溅射系统制备的钡铁氧体薄膜晶化温度的比较，结果表明，对靶溅射系统制备的薄膜的晶化温度低于直流磁控溅射系统制备的薄膜，Ba-2 O3薄膜的晶化温度比直流磁控溅射系统制备的薄膜的晶化温度低，Ba-2 O3薄膜的晶化温度比直流磁控溅射系统制备的薄膜的晶化温度低，Ba-2 O3薄膜的晶化温度比直流磁控溅射系统制备的薄膜的晶化温度低。铁氧体薄膜在2 ~ 3 kOe范围内，垂直方向矩形比约为0.8。本研究采用双磁头对钡铁氧体超导硬磁盘进行记录，获得了100 kbpi左右的记录密度。通过优化沉积过程中的氧分压和退火时间等制备条件，可以提高该值，研究结果表明，本项目提出的技术适用于实际的记录介质的大规模生产。

In order to develope a new fabrication technique for near future high density magnetic recording media, a facing target sputtering system has been built. In this system, the ferromagnetic thin films can be deposited with high rate even when the thick iron target was used. From our previous research, it was found that the Ba-ferrite thin films can be prepared at high substrate temperature. Although the Ba-ferrite thin films with excellent characteristics for magnetic recording media, it is not suitable for practical mass prodauction. In this study, we proposed a new technique for fabrication of high density recording media with high rate.The Ba-ferrite thin films were deposited at room temperature and succsessively annealed to crystallize. In comparison with the crystallization temperature of Ba-ferrite thin films prepared both a conventional dc magnetron sputtering system and the facing targets sputtering system, it was found that the crystallization temperature of the films prepared by the facing target sputtering system is lower than of the films prepared by the dc magnetron sputtering system.The coercivities of the Ba-ferrite thin films are in the range from 2 to 3kOe and squareness ratio is about 0.8 in perpendicular direction. These vakues are suitable for high density magnetic recording media.The recording density obtained in this research is about 100kbpi for the Ba-ferrite supttered rigid disks by using a MIG type head. This value will be improved by optimizing the preparation conditons such as oxygen partial gas pressure during the deposition and annealing time.From the results of our reseach, it was found that the technique propsed in this project is applicable for practical mass production of recording media.