MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain a magnetic recording medium which permits simultaneous improvement of short wavelength output and long wavelength output by specifying the average gain size and planar ratio of hexagonal ferrite magnetic powder within a specific range and further specifying the product of the specific surface area and planar ratio to a specific value or below. CONSTITUTION:The average grain size of the hexagonal ferrite magnetic powder is 0.03-0.1mum and the planar ratio is 3-5 and further the product of the specific surface area and planar ratio is <=200m<2>/g. The squareness ratio Rs in the vertical direction of the magnetic recording medium is preferably specified within a 0.5<=Rs<=0.75 range. The squareness ratio Rs in the vertical direction is easily controlled by changing conditions for an orientation treatment. Such hexagonal ferrite magnetic powder is dissolved and dispersed together with a resin binder in an org. solvent and is coated as a magnetic coating compd. on a base film to form the magnetic layer. The coercive force in the perpendicular direction among the magnetic characteristics of the magnetic layer is preferably made 600-1,500(Oe).