Optimization of tunneling magnetotransport and thermal properties in magnetic tunnel junctions by rapid thermal anneal

Abstract

We report on a systematic investigation of rapid thermal anneal (RTA) effects on the properties of FeMn exchange-biased magnetic tunnel junctions (MTJs). The tunneling magnetoresistance (TMR) in an as-grown MTJ is found to be similar to27%, whereas the TMR in MTJs annealed by RTA increases with annealing temperature up to 300 degreesC, reaching similar to46%. A significant change in the effective barrier thickness (t(eff)) and height (Phi(eff)) occurs within 10 s during RTA. Transmission electron microscopy and X-ray reflectivity studies demonstrate that the interface of the alumina tunnel barrier for the MTJ annealed by RTA became sharper and clearer, giving rise to the enhanced TMR. (C) 2003 Elsevier B.V. All rights reserved.