Nondestructive readout, random access cross-tie wall memory system

Abstract

A nondestructive readout, random access memory system is disclosed. The memory is formed of a plurality of discrete thin ferromagnetic film memory elements in which binary data are stored as the presence, or absence, of cross-tie, Bloch-line pairs. Column lines and row lines form a matrix array of the memory elements, one at each column line, row line intersection. Cross-tie, Bloch-line pairs are formed in the memory elements by the selective coincidence of row line and column line write drive fields while readout of the presence, or absence, of the cross-tie, Bloch-line pair is by a coincident row line read drive field and a column read current signal that flows through the memory elements aligned along a selected column. A read amplifier is differentially coupled across the one fully selected memory element to detect a first, or second, opposite polarity output signal that is indicative of the presence, or absence, of a cross-tie, Bloch-line pair at the one fully selected memory element.