Patent ID: 6723450
Filing Date: 2004-04-20
Classification: G11B,Y10T

Abstract:
A magnetic recording medium comprising:a substrate; an underlayer on the substrate; and a magnetic recording layer comprising a lower granular cobalt alloy ferromagnetic film on the underlayer and having its magnetic moment oriented in a first direction, nonferromagnetic spacer film located on and in contact with the lower ferromagnetic film, and an upper granular cobalt alloy ferromagnetic film located on and in contact with the spacer film and having its magnetic moment oriented in a second direction substantially antiparallel to said first direction, the magnetic moment per unit area of the upper ferromagnetic film being greater than the magnetic moment per unit area of the lower ferromagnetic film and the lower ferromagnetic film being coupled to the upper ferromagnetic film predominantly by dipole fields across the spacer film, and wherein the lower ferromagnetic film is the one and only one ferromagnetic film between the spacer film and the substrate, whereby the recording layer has a net magnetic moment oriented substantially in one of said first and second directions in the absence of an applied magnetic field.