US 6,641,891 B2 · Magnetic recording medium

Abstract

Provided is a particulate magnetic recording medium having good processing properties and being inexpensive to produce, similar to prior recording media, wherein by controlling the magnetic clusters that appear due to recording at short wavelengths and thinning of the magnetic layer, good high-density characteristics are achieved in combination with MR heads. The magnetic recording medium comprising an essentially nonmagnetic lower layer and a magnetic layer comprising a ferromagnetic powder and a binder in this order, wherein the magnetic layer has a thickness ranging from 0.01 to 0.15 μm and a coercivity equal to or higher than 159 kA/m, ferromagnetic particles contained in the ferromagnetic powder have a size less than ½ of the minimum recording wavelength, and an average size of magnetic cluster at DC erase is equal to or higher than 0.5×104 nm2 and less than 5.5×104 nm2.

Claims19

Dependent claims

A magnetic recording medium, comprising:

an essentially nonmagnetic lower layer;
and a magnetic layer comprising a ferromagnetic powder and a binder, the magnetic layer located over the lower layer,
wherein said magnetic layer has a thickness ranging from 0.01 to 0.15 μm and a coercivity equal to or higher than 159 kA/m, and the ferromagnetic particles contained in the ferromagnetic powder have a size less than 0.15 μm, and an average size of magnetic cluster at DC erase is equal to or higher than 0.5×104 nm2 and less than 5.5×104 nm2, and wherein the essentially non-magnetic lower layer has either no magnetic properties or magnetic properties to a degree not affected by recording information to the magnetic layer.

Dependencies are inferred from the claim text.

Magnetic recording medium

Life of this patent

Magnetic recording medium

Life of this patent

Abstract

Claims19