Sputtered sandwich heads for high-density digital video recording

Abstract

A sandwich type of head for application in high-frequency and high-density digital video systems is described. Amorphous CoNbZr films laminated with an Al/sub 2/O/sub 3/ insulator layer are used as core material. The influence of rotating and static field annealing on the domain structure and on the permeability is discussed. In order to achieve a sufficiently high efficiency, a polycrystalline ferrite back yoke is applied. Sandwich heads with several ceramic materials in the contact plane are evaluated. The performance of the heads is investigated on the basis of a signal-to-noise criterion, defined specially for the digital video application. A sandwich head made with 2 mu m*5 mu m amorphous CoNbZr, laminated with 0.1 mu m Al/sub 2/O/sub 3/, between glass-ceramic substrates fulfils the requirement on MP tape.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>