Newly developed hot-pressed ferrite head

Abstract

A new type of ferrite called hot pressed ferrite (HPF) which is processed at a very high temperature and pressure during sintering, and which has almost the same density and lack of porosity as single crystal ferrite is described. Furthermore, HPF has many advantages over single-crystal ferrites, including the fact that it is isotropic. The permeability, expansion coefficients, and wearing characteristics of an HPF ingot are identical in all directions, which facilitates head design and manufacture. The magnetic, physical, and ether properties of HPF are described in detail and these properties are compared with those of conventional, high-density, and single-crystal ferrites. The way HPF can be used to design heads giving improved signal-to-noise ratio, higher resolution, and exceptionally long life is also described. The experimental results relate mainly to heads for audio, video, and instrumentation recording.