GMR head for helical-scan recording with a 5000-h head life

Abstract

We describe a giant magnetoresistance (GMR) head for helical-scan recording that overcomes the problems of wear, corrosion, and thermal spikes. A flux guide GMR head is built on a very thin silicon structure that is protected by low-wear bearing materials. We describe both the design of the flux guide microstructure that provides a high-bandwidth path for the flux to the GMR spin-valve sensor and the investigation of bearing materials that give low wear rate with acceptable pole tip recession. Avoiding large closure domains gives the flux guide a permeability greater than 1000 for a bandwidth better than 100 MHz. A bearing structure of Al/sub 2/O/sub 3/SiC gives a head life in excess of 5000 h. Tests with a 19-mm data recorder using conventional dual-layer metal particle tape suggest that this GMR head will support a threefold increase over current recording densities and still allow the reproduction of previous generation recordings.