| 摘要 |
PURPOSE:To obtain a high-capacity and inexpensive medium for vertically magnetized recording which is superior in recording density characteristic, by using a polyethylene terephthalate film, where the roughness of the surface is set to a certain level or below, as a supporting material. CONSTITUTION:About 0.01-1wt% powder of an inert inorganic compound (such as silica. kaolin, and calcium phosphate) is mixed in polyethylene terephthalate (or polyethylene naphthalate), and this mixture is formed into a film to obtain a film where the surface roughness (CLA) is <=0.01mu (i) and the maximum projection height is <=0.1mu (ii), and an Ni-Fe alloy film (soft magnetic material layer) having about 0.2-1.5mu thickness and a Co-Cr alloy film (vertically magnetized film layer) having a thickness of about 0.2-1.5mu are provided on the surface of this film, thus producing a medium for vertically magnetized recording. It is desirable that the absolute value of warp (kp, unit%) of the recording material is <=30, and a lubricant applied layer may be provided on the surface of the supporting material in the opposite side of the recording layer. |
