PERPENDICULAR MAGNETIC RECORDING MEDIUM AND A METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM@AN OBJECT OF THE PRESENT INVENTION IS TO APPROPRIATELY CONTROL THE QUANTITY OF OXIDE CONTAINED IN A MAGNETIC LAYER IN ORDER TO CONTROL OF THE CRYSTAL GRAINS AND THE SEGREGATION STRUCTURE FOR ENSURING LOW NOISE CHARACTERISTIC IN GRANULAR MAGNETIC LAYER THAT CONSISTS OF FERROMAGNETIC CRYSTAL GRAINS AND NONMAGNETIC GRAIN BOUNDRY REGION OF MAINLY OXIDE SURROUNDING THE GRAINS.@MEANS TO SOLVE THE PROBLEM@A PERPENDICULAR MAGNETIC RECORDING MEDIUM OF THE INVENTION COMPRISES A GRANULAR MAGNETIC LAYER AND A NONMAGNETIC UNDERLAYER COMPOSED OF A METAL OR AN ALLOY HAVING HEXAGONAL CLOSEST-PACKED CRYSTAL STRUCTURE. THE FERROMAGNETIC GRAINS IS COMPOSED OF AN ALLOY CONTAINING AT LEAST COBALT AND PLATINUM. THE VOLUME PROPORTION OF THE NONMAGNETIC GRAIN BOUNDARY REGION OF MAINLY OXIDE IS IN THE RANGE FROM 15TO 40OF THE VOLUME OF THE MAGNETIC LAYER.