STUDY ON NANO-STRUCTURIZATION AND MAGNETICAL ISOLATION OF Sm-Co MAGNETIC THIN FILMS FOR ULTRA-HIGH DENSITY INFORMATION STORAGE APPLICATION

SmCo5合金(以下简称SmCo)在所有磁性材料中具有最大的晶态磁各向异性常数，因此，如果降低磁化转变体积、晶粒尺寸或晶团团聚尺寸，用于高密度存储，它可以保持剩余磁化而不去磁，与其他材料相比。在较高的M_S材料如SmCo、NdFeB、FePT和较低的M_S材料如钡铁氧体之间，考虑了哪种介质更适合于100-200 GB/in^2的高密度存储。结果表明，如果介质的颗粒尺寸和磁层厚度可以减小到10 nm或更小，那么高M_S材料是合适的。由于垂直存储的磁化强度具有较窄的磁化转变长度，因此M_S越高，产生的读出电压就越高。为了制备具有垂直磁各向异性的SmCo薄膜，引入铜亚层是有效的。…此外，铜的扩散和Sm原子的结合保护了SmCo层的氧化，最大的优点是SmCo膜可以不需要保护层来防止氧化。对磁化机理的分析表明，磁化电荷是由于单畴磁化的相干旋转所致。另一方面，为了获得具有平面磁各向异性的SmCo薄膜，掺入Cr亚层是有效的。磁化强度的变化是由壁面运动引起的。除铜、铬外，未发现其他有效元素。为了夸大SmCo薄膜的垂直各向异性，在SmCo/Cu/Cr结构中同时使用铜和铬是最合适的。扫描电子显微镜观察发现，SmCo薄膜表面的颗粒尺寸在20-100 nm之间，在10 nm左右的颗粒组成团簇。由dH/dT-Hc曲线得到的磁化反转曲线和用Scherrer方程计算的X射线衍射分析表明，SmCo薄膜的磁化反转主要是由尺寸在10 nm左右的单畴粒子的磁化反转引起的。较少

SmCo_5 alloy(here after referred simply as "SmCo") possesses the largest crystalline magnetic anisotropy constant of all magnetic materials, so that it can retain remanent magnetization without demagnetization to compare the other materials if the magnetization switching volume, grain size or the size of grain agglomeration of grain cluster, is reduced for high density storage. The consideration is taken which is more suitable storage media for high density storage of the regime 100-200Gb/in^2 between the high M_s materials as SmCo, NdFeB, FePt and the lower M_s materials as Ba-ferrite. The result is that the high M_s materials are suitable if the grain size and magnetic layer thidcness of media can be reduced to 10nm or less. Since the perpendicularly stored magnetization has much narrower magnetization transition length, the higher M_s generates the higher readout voltage.To generate the SmCo films with perpendicular magnetic anisotropy, the incorporation of Cu sublayer is effective. … More The diffusion of Cu combine with Sm atoms whim protects the oxidation of SmCo layer ; The great merit is that SmCo films ca do without the protective layer for oxidation proof. The analysis of magnetization mechanism shows that magnetization charge is due to the coherent rotation of single-domain magnetization. On the other hand, to generate the SmCo films with planer magnetic anisotropy, the incorporation of Cr sublayer is effective. The magnetization change is due to the wall motion. No other affective element is found except Cu and Cr. To bring out exaggeratedly the perpendicular anisotropy for SmCo film, it is most suitable to use both Cu and Cr layers in the construction of SmCo/Cu/Cr. SEM observation on the SmCo film surface reveals the grain size of 20-100nm TEM observation reveals grains of around 10nm constitute clusters. The analysis of magnetization reversal obtained by the plot of dH/dt vs. H_c and XRD analysis calculated with Scherrer's equation concluded that the magnetization change of SmCo films is caused mainly by magnetization reversal of single domain partides with around 10nm in size. Less