Magnetoresistance of submicrometre multilayer Wheatstone bridges as a probe of magnetic reversal mechanism.

The magnetoresistance of elliptical NiFe/Cu/Co multilayer rings with deep submicrometre widths contacted in a Wheatstone bridge configuration has been characterized. The rings show large voltage signals corresponding to magnetic configurations in which either the Co or the NiFe layer is in a vortex state. This result indicates that asymmetrically placed 360° domain walls can be present in the vortex states attained during the reversal of the magnetic layers. Minor loop cycling generates a range of possible remanent resistance levels in the rings, which makes these devices interesting candidates for multiple-bit-per-cell magnetic random access memory or for non-volatile programmable logic devices. [ABSTRACT FROM AUTHOR]