VERTICAL MAGNETIC RECORDING MEDIUM AND ITS PRODUCTION

PURPOSE:To increase a packing rate of a magnetic substance into a pore and improve produtivity setting up electrolytic conditions so that the thickness of a residual barrier layer on the bottom of the pore is included in a specific range when the diameter of the pore is expanded up to a value satisfying conditions necessary for the magnetic characteristics of high density recording. CONSTITUTION:To improve the magnetic substance packing rate, it is necessary to set up the thickness of the barrier layer after the expanding processing of the pore diameter to a value enabling current supply in a voltage impressed at the electrolytic deposition of the magnetic substance metal, i.e. 80-280Angstrom . The accelerating degree of dussolution of the barrier layer on the bottom part of the pore depends upon the conditions of electrolytic voltage, electrolytic time, etc. In the expanding processing of the pore diameter, constant current electrolysis is executed by small current, and when electrolytic voltage reduced in accordance with time passage reaches a prescribed voltage, the processing is switched to constant voltage electrolysis and the electrolysis is stopped when current is stabilized.