Strong temperature dependence of antiferromagnetic coupling in CoFeB/Ru/CoFeBN. Wiese1, 2, T. Dimopoulos1, M. Rührig1, J. Wecker1, G. Reiss2, J. Sort3 and J. Nogués3
1 Siemens AG Corporate Technology - Paul-Gossen-Straße 100, 91052 Erlangen, Germany
2 University of Bielefeld, Nano Device Group - Universitätsstraße 25, 33615 Bielefeld, Germany
3 Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona - 08193 Bellaterra, Spain
received 22 April 2007; accepted in final form 4 May 2007; published June 2007
published online 25 May 2007
The temperature dependence of saturation and spin-flop fields for artificial ferrimagnets (AFi) based on antiparallel coupled CoFeB/Ru/CoFeB trilayers has been investigated in a temperature range between 80 K and 600 K. The results presented in this paper are relevant for magnetic devices using this system, e.g. magnetic-random access memory based on spin-flop switching. In good accordance to the theory, the saturation field behaves like with a characteristic temperature of . Within this model, the Fermi velocity for the Ru layer is of the order of , therefore, explaining the strong variation of the coupling strength with the temperature in Ru-based AFi. Furthermore, a strong uniaxial anisotropy of with a small angular distribution of the anisotropy axes is observed for the AFi trilayers based on amorphous CoFeB alloys.
75.70.-i - Magnetic properties of thin films, surfaces, and interfaces.
75.50.Kj - Amorphous and quasicrystalline magnetic materials.
75.30.Gw - Magnetic anisotropy.
© Europhysics Letters Association 2007