Effects of an Os layer on the magnetic properties of CoFe/IrMn

Abstract

The uses of Os as an antidiffusion and buffer layer in IrMn exchange coupled CoFe film were investigated. For the purpose of antidiffusion, the inserted Os layer showed a distinct improvement of S>0.9, with H-C slightly increasing by 1.6 times for the CoFe/Os/MnOs multilayer after 400 degrees C annealing, even though the Os thickness was as thin as 0.3 nm. Furthermore, with a 0.3 nm Os barrier, the 350 degrees C annealed CoFe/Os/IrMn/CoFe showed almost the same magnetic behavior as the as-deposited state, while the H-ex of the upper part of the CoFe/Os/IrMn changed from 100 to 190 Oe. In addition, as a buffer layer, the Os buffer layer could enhance the diffraction peak intensities of IrMn(111)/Os(002) and CoFe (111), and the H-ex of CoFe/IrMn was proportional to the Os thickness. A 120 Oe of H-ex was achieved by using an 11 nm Os buffer layer in a CoFe 10 nm/IrMn 15 nm bottom type film. These results show that Os has the potential to be an antidiffusion and buffer layer in a magnetic multilayer. (C) 2006 American Institute of Physics.