US 6,641,891 B2
Magnetic recording mediumGeneral
US 6,641,891 B2
Magnetic recording medium
Tech Center:
1700 Chemical and Materials Engineering
Examiner:
Stevan A. Resan
Art Unit:
1773 Chemical Apparatus, Separation and Purification, Liquid and Gas Contact Apparatus
Inventors:
Hiroaki Doushita; Nobuo Yamazaki
Assignee:
Priority:
03/28/01
Filed:
03/27/02
Granted:
11/04/03
Expiration:
05/14/22
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 &mgr;m 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.
Cooperative Patent Classification (CPC)
Y10Y10T428/256Y10TG11B5/714G11B