Enhancement of exchange bias by ultra‐thin Mn layer insertion at the interface of Mn‐Ir/Co‐Fe bilayers

Abstract

Abstract Effects of ultra‐thin Mn, Ru, Pd, Ta, Gd, and Tb layer insertion at the interface on the exchange bias of Mn 75 Ir 25 /Co 70 Fe 30 bilayers were investigated. Unidirectional anisotropy constant, J K , of the bilayer was significantly enhanced from 0.46 erg/cm 2 to 0.84 erg/cm 2 with the insertion of 0.5‐nm‐thick Mn layer, while it was reduced with increasing the inserted layer thickness for the other materials. The value of 0.84 erg/cm 2 was not obtained in the variation of J K with respect to the chemical composition of Mn‐Ir layer in a range of Ir content of 0 ∼ 40 at.%. The cause of the enhancement of J K with ultra‐thin Mn insertion might be due to the modification of antiferromagnetic spin structure at the interface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)