Magnetoresistive readout transducer for sensing magnetic domains in thin film memories

摘要

A magnetoresistive bridge formed of specific magnetoresistive elements is disposed on a monolithic substrate in conjunction with a thin film shift register. At least one (active) element of the bridge is placed in the region of the last domain position in a shift register channel. At least one other (balance) element of the bridge is spaced from the magnetic structure, whereby the combination balances the bridge while compensating for temperature variations. In one embodiment, two active arms of a four-element bridge are arranged such that a bipolar sense signal is obtained as a "1" passes into the last domain position. The remaining balance elements are spaced from the magnetic structure to provide compensation for noise, as well as temperature variations. A readout circuit provides an amplifier combination which samples the bipolar signal during selected time windows to enhance the sense signal output generated by the bridge.