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THERMALLY STABLE ULTRA HIGH DENSITY THIN FILM MAGNETIC MEDIA

热稳定超高密度薄膜磁性介质

基本信息

批准号：
10305027
负责人：
TAKAHASHI Migaku
金额：
$ 5.57万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

All the thin film media used in this study were prepared with an in-line thin film deposition machine, which has 6 separated chambers for sputtering. The ultimate vacuum pressure for each chamber was better than 3×10ィイD1-9ィエD1 Torr. To remove impurities from the substrate surface, prior to film deposition, dry-etching was performed by rf sputtering. The compositions of magnetic layer were CoCrPt, CoCrTaPt and CoCrPtB. The Cr, Pt, Ta B content was widely varied. The results get from the evaluation of magnetic properties, microstructure and read-write properties are written below.1. The intergranular magnetic coupling and the grain size in CoCrPt media with B addition are both reduced. On the other hand, the substitution of Cr with Ta in CoCrPt media increases the grain size. The read-write evaluation shows that the addition of B into CoCrPt reduces the media noise significantly. However, the media noise of CoCrTaPt media is lower compared with CoCrPtB, though the CoCrTaPt media has larger grain size compared with CoCrPtB media. This is due the relatively lower intergranular exchange coupling in CoCrTaPt media, compared with CoCrPtB media. From this result, we can conclude that the addition of both Ta and B into CoCrPt media is effective to reduce the media noise.2. To realize a media which is thermally stable, the thermal stability factor vィイD2actィエD2KィイD2uィエD2ィイD1grainィエD1/kT must be larger than 85.It is concluded that to realize low noise media which is thermally stable, the coercivity HィイD2cィエD2, the anisotropy field HィイD2kィエD2ィイD1grainィエD1 and the magnetocrystalline anisotropy energy KィイD2uィエD2ィイD1grainィエD1 should be 5 kOe, 14 kOe and 2.1×10ィイD16ィエD1 erg/cmィイD13ィエD1, respectively. With the assumption that the saturation magnetization is MィイD2sィエD2=300 emu/cmィイD13ィエD1, the squareness S=0.7, remanence magnetization MィイD1rィエD1=210 emu/cmィイD13ィエD1, film thickness tィイD2magィエD2=15 nm, vィイD2actィエD2KィイD2uィエD2ィイD1grainィエD1/kT=85, magnetic cluster GDィイD2actィエD2=12 nm.

本研究中使用的所有薄膜介质均采用在线薄膜沉积机制备，该机具有 6 个独立的溅射室。每个室的极限真空压力优于3×10ィイD1-9ィエD1 Torr。为了去除基板表面的杂质，在薄膜沉积之前，通过射频溅射进行干法蚀刻。磁性层的成分为CoCrPt、CoCrTaPt和CoCrPtB。 Cr、Pt、Ta B 含量变化很大。磁性能、显微组织和读写性能的评价结果如下： 1．添加 B 的 CoCrPt 介质中的晶间磁耦合和晶粒尺寸均减小。另一方面，在 CoCrPt 介质中用 Ta 替代 Cr 增大了晶粒尺寸。读写评估表明，CoCrPt中添加B显着降低了介质噪声。然而，尽管与 CoCrPtB 介质相比，CoCrTaPt 介质具有更大的晶粒尺寸，但与 CoCrPtB 介质相比，CoCrTaPt 介质的介质噪声较低。这是由于与 CoCrPtB 介质相比，CoCrTaPt 介质中的晶间交换耦合相对较低。从该结果可以看出，CoCrPt介质中同时添加Ta和B对于降低介质噪声是有效的。 2．要实现热稳定介质，热稳定因子vィイD2actィエD2KィイD2uィエD2ィイD1grainィエD1/kT必须大于85。由此得出，要实现热稳定的低噪声介质，矫顽力HィイD2cィD2、各向异性场HィイD2kィエD2ィイD1grainィエD1 和磁晶各向异性能量KィイD2uィエD2ィイD1grainィエD1应分别为5 kOe、14 kOe和2.1×10ィイD16ィエD1 erg/cmィイD13ィD1。假设饱和磁化强度MィイD2sィエD2=300 emu/cmィイD13ィエD1，方形度S=0.7，剩磁MィイD1rィエD1=210 emu/cmィイD13ィエD1，膜厚tィイD2magィエD2=15 nm， vィイD2actィエD2KィイD2uィエD2ィイD1grainィエD1/kT=85，磁团簇GDィイD2actエD2=12 nm。