Enhancement of tunneling magneto resistance by inserting an amorphous nonmagnetic FeZr layer in magnetic tunnel junctions

Abstract

An amorphous metallic FeZr layer is inserted inside the bottom magnetic layer in exchange-biased CoFe/Al2O3/CoFe magnetic tunnel junctions (MTJs). At room temperature, the tunneling magnetoresistance (TMR) increases from 25% to 36% before annealing, and from 45% to 52% after annealing. The junction resistance also increases with the FeZr thickness. The higher quality of the MTJ is attributed to the improved Al-oxide barrier due to the amorphousness of the FeZr layer. (C) 2004 Elsevier B.V. All rights reserved.