| 摘要 |
PURPOSE:To realize high density and a high output for a vertical magnetic recording medium, by providing a vertical magnetic anisotropic magnetic layer of magnetic wall shift type on the back of a vertical magnetic anisotropic magnetic layer. CONSTITUTION:A vertical magnetic anisotropic magnetic layer 3 of magnetic wall shift type is laminated on a vertical magnetic anisotropic magnetic layer 2. The coercive force of the layer 2 is smaller than that of the layer 3, and the saturated magnetization of the layer 2 is set larger than the residual magnetization of the layer 3 along with a larger anisotropic magnetic field. The magnetic domain width (a) of the layer 2 in a state of demagnetization decreases as the saturated magnetism MS of the magnetic layer increases and then has a reduction with the decrement of the anisotropic constant Ku. When the writing is carried out to such a recording medium, the width (a) of the layer 3 is equalized to that of the layer 2. This width (a) can be set at a small value, and therefore, the recording denity is increased. Furthermore, a magnetic wall is shifted easily by a writing magnetic field to the layer 3 with a relation of the above-mentioned coercive force, and at the same time the anisotropic magnetic field of the layer 2 is not tilted by that of the layer 3 in relation to the anisotropic magnetic field. The surface magnetization of the layer 3 is increased more than the conventional one with an increment of output since the magnetization of the layer 2 is produced in response to the magnetization of the layer 3. |
