Magnetic recording medium

摘要

Non-magnetic powder of particles for non-magnetic lower layer applications is provided that enables a multilayer coating type magnetic recording medium having good surface smoothness to be obtained. The particles are iron compound particles having a long axis with a standard geometrical deviation, as obtained from a transmission electron microscope image, that is greater than 1.5, and a short axis with a standard geometrical deviation, as obtained from a TEM image, that is greater than 1.35. The invention can be ideally applied with respect to particles that, when L is the average length of the long axis and D is the average length of the short axis, obtained from TEM images, satisfy at least one of the following equations (1) and (2). (1): (Cumulative number of particles having a long-axis length of not more than L/2) / (cumulative number of particles having a long-axis length of not more than 2L) ‰§ 0.5; (2): (Cumulative number of particles having a short-axis length of not more than D/2) / (cumulative number of particles having a short-axis length of not more than 2D) ‰§ 0.5. The iron compound particles may be hematite or iron oxyhydroxide.