A high resolution flying magnetic disc recording system with zero reproduce spacing loss

A novel method has been developed for reducing the reproduce spacing loss and thereby potentially allowing increased linear densities on a disc media while maintaining a reasonable flying height. A laminated magnetic recording media is composed of a high coercivity layer in which the data signals are stored, and a thin, low coercivity, high permeability overlayer called a keeper layer. A small DC bias applied to the head saturates a section of the keeper layer, forming a virtual gap that is in direct contact with the high coercivity storage layer. This virtual gap functions as a transducing zone that enables a signal flux to be transferred from unsaturated keeper regions to the pole pieces of the flying head. Experimental results show that a considerable reduction, if not elimination, of the reproduce spacing loss is achieved using the keepered disc. Additionally the keepered disc virtual gap was found to be about 10% smaller than the physical gap in the flying head that induced it. A series of simulations were conducted using finite difference models which confirmed the trends observed in the experimental data