Patent ID: 7531251

Claim:
A magnetic recording medium comprising: a nonmagnetic support having a thickness less than 4.5 μm and a width of 8 mm; a ferromagnetic metal layer on a surface of the nonmagnetic support; a carbon protective film layer including a ferromagnetic metallic material on the ferromagnetic metal layer; a reinforcing layer on the other surface of the nonmagnetic support; and a back coating layer under the reinforcing layer, wherein, the magnetic recording medium has a flexural rigidity EI of 5.9×10 −8 to 1.3×10 −7 N·m when the flexural rigidity EI of the magnetic recording medium is determined by the following equation: EI =(π/4−2/π) W·a 3/ d·b× 9.8×10 −5 , where W is a load that causes an annular test piece having a radius of a cm and a width of b cm which is prepared by cutting a magnetic sheet formed of the magnetic recording medium to undergo a radial displacement d of 0.2π·a.