Galvanomagnetic readout elements for domain tip devices

Abstract

The use of galvanomagnetic readout techniques for producing output signals from magnetic thin film devices based on domain tip (DOT) propagation has been investigated. Whereas methods of inductively sensing the signal from a propagating DOT are limited to the order of 100 μV per output channel per turn of pickup loop, magnetoresistance can be used to produce output signals of several millivolts from a single output channel. In addition to permitting smaller readout elements to be made, magnetoresistance has the further advantage of providing a continuous rather than transient output signal. Two and four electrode configurations, for both the longitudinal magnetoresistance and the planar Hall effect, have been evaluated. The use of isolation slits etched into the magnetic layer to eliminate leakage currents has been investigated as well. The results indicate that small area readout elements with output signals in the range of several millivolts are practical.