Magnetic disk having a magnetic layer comprising a binder and ferromagnetic particles of specified crystallite size and surface area and in which the mechanical loss tangent, tan delta, is within a specified range

摘要

A magnetic disk comprising a nonmagnetic support having provided thereon a magnetic layer comprising a ferromagnetic metal powder and a binder resin, wherein the magnetic layer has a mechanical loss tangent, tan delta , of from 8x10-3 to 6x10-2, measured at a frequency of 110 Hz and in a temperature range of from 20 DEG to 50 DEG C. with a temperature increase rate of 2 deg/min.