Effect of microstructures on exchange anisotropy in Mn-Ir/Ni-Fe exchange-biased mutilayers with various stacking structures

Abstract

The magnetic properties and the microstructures of the Mn-Ir/Ni-Fe multilayers with various stacking structures and buffer layer materials have been investigated. The (111) texture of Mn-Ir/Ni-Fe is obtained in the top structures with Ta or Zr buffer. However, all mutilayers which contain Mn-Ir films deposited on Ni-Fe films exhibit high H/sub ex/, regardless of the [111] preferred orientation of Mn-Ir film. The TS multilayers which show high H/sub ex/ have large Mn-Ir grains at the interface, compared with BS multilayers without exchange anisotropy. The multilayers which reveal the exchange anisotropy also have the grain-to-grain epitaxial tendency at the interface of Mn-Ir/Ni-Fe. It is concluded that the H/sub ex/ is not related to the [111] texture of the Mn-Ir film, but related to the grain size of the Mn-Ir film and the morphology at the interface between the Mn-Ir and the Ni-Fe grains.