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

SmCo_5合金（以下简称“SmCo”）在所有磁性材料中具有最大的晶体磁性各向异性常数，因此，如果减小磁化开关体积、晶粒尺寸或晶粒团簇的晶粒团聚尺寸以实现高密度存储，则可以保持剩余磁化而不退磁，与其他材料相比。在SmCo、NdFeB、FePt等高M_s材料和ba -铁氧体等低M_s材料之间，比较了哪种存储介质更适合于100-200Gb/in^2范围内的高密度存储。结果表明，当介质的晶粒尺寸和磁层厚度减小到10nm以下时，高M_s材料是合适的。由于垂直存储磁化强度的磁化跃迁长度要窄得多，因此较高的M_s产生较高的读出电压。为了制备具有垂直磁各向异性的SmCo薄膜，Cu亚层的加入是有效的。Cu与Sm原子结合后的扩散可以保护SmCo层的氧化；SmCo薄膜最大的优点是不需要氧化保护层。磁化机理分析表明，磁化电荷是由单畴磁化的相干旋转引起的。另一方面，Cr子层的掺入是制备具有平面磁各向异性的SmCo薄膜的有效方法。磁化的变化是由于壁面运动引起的。除了Cu和Cr外，没有发现其他因素对SmCo膜的垂直各向异性有影响。为了突出SmCo膜的垂直各向异性，在SmCo/Cu/Cr结构中，Cu和Cr两层同时使用是最合适的。SEM观察SmCo膜表面晶粒尺寸为20 ~ 100nm， TEM观察显示10nm左右的晶粒组成团簇。通过dH/dt vs. H_c曲线和Scherrer’s方程计算的XRD分析得出，SmCo薄膜的磁化变化主要是由10nm左右的单畴粒子的磁化反转引起的。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