Magnetic recording medium

Abstract

A magnetic recording medium includes a nonmagnetic support body, and a magnetic layer containing magnetic powder, in which the magnetic powder contains ε-Fe 2 O 3 crystal (including a case of substituting a portion of Fe site with a metal element M), a product of residual magnetization and a thickness of the magnetic layer is from 0.5 mA to 6.0 mA, and a squareness ratio which is measured in a longitudinal direction of the magnetic layer is 0.3 or less.

What is claimed is: 
     
         1 . A magnetic recording medium comprising:
 a nonmagnetic support body; and   a magnetic layer containing magnetic powder,   wherein the magnetic powder contains ε-Fe 2 O 3  crystal (including a case of substituting a portion of Fe site with a metal element M),   a product of residual magnetization and a thickness of the magnetic layer is from 0.5 mA to 6.0 mA, and   a squareness ratio which is measured in a longitudinal direction of the magnetic layer is 0.3 or less.   
     
     
         2 . The magnetic recording medium according to  claim 1 ,
 wherein the thickness of the magnetic layer is from 30 nm to 100 nm.   
     
     
         3 . The magnetic recording medium according to  claim 1 ,
 wherein an spontaneous magnetization amount of the magnetic powder is from 5 emu/g to 25 emu/g.   
     
     
         4 . The magnetic recording medium according to  claim 1 ,
 wherein coersive force of the magnetic layer is from 2000 Oe to 4500 Oe.   
     
     
         5 . The magnetic recording medium according to  claim 1 ,
 wherein physical volume of the magnetic powder is from 800 nm 3  to 4000 nm 3 .   
     
     
         6 . The magnetic recording medium according to  claim 1 ,
 wherein a filling rate of the magnetic powder is 30% or more.   
     
     
         7 . The magnetic recording medium according to  claim 1 ,
 wherein a magnetic resistance effect type head of a tunnel type is used as a reproduction head.