| 摘要 |
PURPOSE: To provide a base film for a magnetic recording medium having excellent travelling stability and advantageous for the production cost, and further to obtain a magnetic recording medium which can maintain electromagnetic conversion characteristics and improves the film forming rate of a ferromagnetic metal thin film. CONSTITUTION: The surface roughness of the back surface of the base film is specified to 4.5-20nm center line average roughness Ra , 35-350nm ten-point average roughness Rz , and 40-400nm max. roughness Rmax . The surface where a magnetic layer is to be formed is optimized considering the electromagnetic conversion characteristics and travelling property of a ferromagnetic metal thin film to be formed thereon so that the surface roughness is controlled to <=10nm center line average roughness Ra , <=80nm ten-point average roughness Rz , and <=150nm max. height Rmax . Or, projections of 40-100nm height are formed by 0.5×10<4> to 10×10<4> particles/mm<2> and projections of 15-35nm height are formed by 10×10<4> to 5000×10<4> particles/mm<2> .
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