Studies on the magnetic anisotropy in single-layer films and magnetic interaction in bilayer films :

1.对铁磁共振进行了理论研究。为了分析磁各向异性，已知Smit和Beljers提出的精确解和Kittel提出的近似解。然而，Kittel提出的有效退磁因子（N_x^e，N_y^e）的公式是不正确的。我们导出了一个新的N_x^e和H_y^e方程，得到了薄膜的共振方程。利用这种方法，得到了静磁场在薄膜平面内旋转时，具有单轴各向异性和四重各向异性的薄膜的共振方程，计算了六种排列：（1）垂直各向异性，（2）面内各向异性，（3）单晶（001）面，（4）单晶（011）面，（5）单晶（111）面，（6）斜向各向异性薄膜.实验研究了Co和Ni薄膜的磁各向异性以及Ni/NiO和NiFe/NiO双层膜的磁电阻。(1)在单层Ni膜中，用铁磁共振观察到一个大的垂直各向异性场。(2)在Co薄膜中，薄膜的周向各向异性场随厚度的减小而增大。(3)研究了Ni/NiO和NiFe/NiO双层膜的磁电阻特性。

1. Theoretical investigation of ferromagnetic resonance (FMR) has been done. To analyze the magnetic anisotropy, exact solution proposed by Smit and beljers and approximate solution by Kittel is known. However, equation of effective demagnetizing factors (N_x^e, N_y^e) by Kittel is not correct. We derived a new equation of N_x^e and H_y^e and we obtained resonance equation for thin films. By this derivation method, the resonance equations of thin films having a uniaxial or a fourfold anisotropy are obtained when a static field is rotated in the film plane, six arrangements are calculated : (1) perpendicular anisotropy, (2) in-plane anisotropy, (3) cubic-crystal (001) face, (4) cubic-crystal (011) face, (5) cubic-crystal (111) face, and (6) oblique anisotropy films.2. Magnetic anisotropy of Co and Ni films and magnetoresistance of bilayer films of Ni/NiO and NiFe/NiO has been experimentally studied. (1) In single layer Ni films, a large perpendicular anisotropy field was observed by FMR.(2) In Co films, Perpendicular anisotropy field increases with decreasing the thickness.(3) In bilayer Ni/NiO and NiFe/NiO films, magetoresistance was studied.