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Preparation and Characterization of Nitride-base Magnetic nanocomposite films

氮化物基磁性纳米复合薄膜的制备及表征

基本信息

批准号：
12650656
负责人：
HASHIMOTO Mitsuru
金额：
$ 1.6万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

In this work, the preparation and characterization of Co-Ti-N films have been conducted. First, we have disclosed the relation between the preparation condition and the structure of the Co-Ti-N films. Co-Ti-N films have been prepared by dc sputtering of Co-Ti complex target in Ar +N_2 gas mixture. For the films deposited at appropriate N_2 partial pressure, the reaction between Ti and N occurs to form TiN during post-deposition thermal anneal. As a result Co and Ti separate with each other, to form Co-TiN nano-composite. The sizes of Co and TiN grains in the longitude direction are about 10 nm in diameter. And fiber-like structure is developed along the normal direction of the film surface. Next the magnetic properties of the Co-TiN nanocomposite films have been investigated. It has been found Co-TiN nanocomposite films with their thickness less than 100 nm show similar magnetization behavior in both longitude and perpendicular directions. However, those films with their thickness abov … More e 100 nm show perpendicular magnetic anisotropy, I.e. perpendicular direction becomes the easy axis of magnetization. Furthermore, the dependence of magnetic properties on the thermal anneal condition and film structure have been investigated. The as-deposited films almost do not show ferromagnetic performance. When the films were annealed at 400 - 700℃, they show clearly ferromagnetic performance and the saturation magnetization increased with increasing anneal temperature. This is because that in the as-deposited state, Co atoms are bonded to Ti and N, upon thermal anneal at elevated temperature, N atoms preferentially react with Ti atoms, therefore, Co is separated. The magnetic properties of the Co-TiN films also depend strongly on the amount of N incorporated into the films. When N amount is too small, the phase separation can not fully proceed. On the other hand, when the N amount is too large, Co is also nitrided except Ti. Both cases will impair the saturation magnetization. Therefore it is important to control the N amount in the film.Beside the magnetic properties, we have found that the resistivity and hardness of Co-TiN nanocomposite films are very high compared with metal and alloy films.According to the result of this research work, we consider the Co-TiN-based nanocomposite films very promising as ultra-high density perpendicular magnetic recording media. Less

本论文主要研究了Co-Ti-N薄膜的制备和表征。首先，我们揭示了Co-Ti-N薄膜的结构与制备条件的关系。在Ar +N_2混合气体中，用直流溅射Co-Ti复合靶制备了Co-Ti-N薄膜。对于在适当的N_2分压下沉积的薄膜，在沉积后的热退火过程中，Ti和N之间发生反应形成TiN。结果Co和Ti相互分离，形成Co-TiN纳米复合材料。Co和TiN晶粒在纵向上的尺寸约为10 nm。并且纤维状结构沿膜表面的法线方向沿着发展。接着研究了Co-TiN纳米复合薄膜的磁性能。发现厚度小于100 nm的Co-TiN纳米复合薄膜在纵向和垂直方向上都表现出相似的磁化行为。然而，厚度大于100 μ m的薄膜， ...更多信息 e 100 nm显示垂直磁各向异性，即垂直方向成为易磁化轴。此外，磁性能的热退火条件和薄膜结构的依赖关系进行了研究。沉积态薄膜几乎不显示铁磁性能。在400 ~ 700℃退火时，薄膜表现出明显的铁磁性能，饱和磁化强度随退火温度的升高而增大。这是因为在沉积状态下，Co原子与Ti和N键合，在高温下热退火时，N原子优先与Ti原子反应，因此，Co被分离。Co-TiN薄膜的磁性能也强烈依赖于N的量纳入到膜中。当N量太小时，相分离不能充分进行。另一方面，当N量太大时，除了Ti之外，Co也被氮化。这两种情况都会削弱饱和磁化强度。Co-TiN基纳米复合薄膜除了具有良好的磁性能外，其电阻率和硬度都比金属薄膜和合金薄膜高，因此，Co-TiN基纳米复合薄膜作为超高密度垂直磁记录介质具有很好的应用前景。少