VERTICAL MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain a recording medium having large mechanical strength and small curling by using polyester consisting essentially of specific repeated units as a base body and forming a thin vertical magnetic film consisting essentially of Co and Co oxide having the axis of easy magnetization in the film thickness direction on the surface thereof. CONSTITUTION:Co is deposited by evaporation using an electron beam on a base body formed by stretching biaxially an unstretched film of polyester contg. >=85mol% repeated units expressed by the formula while gaseous O2 is introduced thereto to form a thin magnetic film consisting of Co and Co oxide having the axis of easy magnetization in the film thickness direction. An Fe-Ni alloy is otherwise deposited by evaporation first on the same base body as the above- described base body and thereafter the thin vertical magnetized film consisting essentially of Co and Co oxide is formed on such alloy film. The thin film type vertical magnetic recording medium having the small decrease in the magnetic characteristic owing to a heat treatment for uncurling is thus obtd.