THE MICROSTRUCTURE AND MAGNETIC PROPERTIES OF PERPENDICULARLY ORIENTED PARTICULATE MEDIA PREPARED IN REVOLVING ALTERNATING MAGNETIC FIELD

Abstract

  We have studied perpendicularly oriented particulate media prepared using a revolving alternating magnetic field. The microstructure on a coating medium of acicular magnetite particles and the magnetic properties were examined. Squareness ratio Rs_z, intrinsic perpendicular magnetic anisotropy K^∗_⊥, and the easy axis depend on the orientation of the magnetic field in coated media. The maximum values of Rs_z and K^∗_⊥ were 0.228 and 6.4×10⁴ erg/cc, respectively. It was determined by observing the bright field image of the microstructure that acicular particles were arranged along the direction normal to the coatingplane in perpendicularly oriented tapes.