Orientation of colloidal magnetically switchable particles

Abstract

Most magnetic media in use today are made by dispersing small magnetic particles in an organic binder and coating the resultant mixture on a support material. The magnetic particles are typically nonspherical and have a magnetization that can change in direction but not in magnitude. Each particle has two stable directions of magnetization, opposite to one another, but aligned with the principal axis of the particle. Because of this coupling of the particle magnetization to the particle axis, the orientation of particles in a magnetic media product contributes to the output level of a recorded magnetic signal and the signal-to-noise ratio. In video applications, particle orientation affects picture sharpness and brightness, and in data recording applications, it affects bit density and error performance.