Temperature dependent biquadratic exchange coupling in Co/Cu (0.94)Mn(0.06) multilayers
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Date
2010-02-05
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Institute of Physics
Abstract
Magnetic interlayer coupling phenomena in systems consisting of ferromagnetic films separated by non-magnetic spacer layers, such as Co/Cu multilayers, are heavily dependent on the thickness and composition of the spacer layer. Usual Co/Cu multilayers exhibit the normal oscillatory RKKY exchange coupling resulting in alternating ferromagnetic/antiferromagnetic magnetic alignment of adjacent layers with increasing Cu thickness. We report on a crucial temperature dependence of this coupling introduced as the non-magnetic spacer layer is substituted by a spin-glass material, such as CuMn. Kobayashi et al. first discovered the extraordinary behaviour of a ferromagnetic exchange coupled Co/CuMn multilayer structure showing an
increasing antiferromagnetic component as the system is cooled below a critical temperature. In order to investigate the magnetic rearrangement throughout the transition temperature in more detail we used polarized neutron reflectometry in specular and off-specular geometry to resolve the orientation of the magnetization in the Co layers. Co/Cu(0.94)Mn(0.06) multilayer samples with a manganese concentration of 6at% in the spacer layer are grown using sputter deposition and quality checked with X-ray reflectivity and diffraction. The onset of a magnetic rearrangement into an antiferromagnetic constitution around 100K is confirmed by neutron reflectivity measurements, revealing the onset of biquadratic interlayer coupling. Simulations of the full two dimensional off-specular scattering points out each layer breaking into magnetic domains. Further magnetic characterisation of the sample using X-Ray magnetic circular dichroism and conventional magnetometry indicate the role of the Mn doping in the magnetic transition into a biquadratic coupling.
Description
Keywords
Temperature dependence, Coupling, Cobalt, Copper, Manganese, Layers, Ferromagnetism, Antiferromagnetism, Magnetic circular dichroism, Neutron reflectors
Citation
Saerbeck, T., Loh, N., Ali, M., Hickey, B. J., Lott, D., Toperverg, B. J., Mulders, A., Stampfl, A. P. J., Klose, F., & Stamps, R. L. (2010). Temperature dependent biquadratic exchange coupling in Co/Cu (0.94)Mn(0.06) multilayers. Poster presented to the 34th Annual Condensed Matter and Materials Meeting 2010, Waiheke Island Resort, Waiheke, Auckland, New Zealand 2 - 5 February 2010. Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2010/