Co-CoO斜め蒸着テープの結晶粒内異方性磁界に関する考察

抄録

We investigated the relationship between the shape of clusters of Co crystallites, obtained by transmission electron microscopy (TEM), and the magnetic anisotropy field of grains (H_k^grain) of Co-CoO obliquely evaporated magnetic tape. Comparison of the former with the latter revealed that the H_k^grain of Co-CoO obliquely evaporated magnetic tape closely correlates with the aspect ratio (N) of clusters of Co crystallites. The magnitude of H_k^grain is defined as that of a magnetic field where the rotational hysteresis loss of the torque curve is zero. We investigated the relationship between the H_k^grain and saturation magnetization M_s, using samples prepared under various conditions. The results showed that H_k^grain becomes asymptotic to the value H_kCo + M_s/2, determined by the maximum value of the shape anisotropy M_s/2 in the region of low M_s. The value of H_k^grain calculated by using a value of N obtained from TEM images was found to be close to the value of H_k^grain obtained by magnetic torque measurement, and this tendency was confirmed qualitatively.