Lattice Misfit Strain as Origin for Biquadratic Interlayer Coupling
R. Jaroszewicz, Z. Bąk and W. Gruhn
Institute of Physics, Pedagogical University, Al. Armii Krajowej 13/15, 42-201 Częstochowa, Poland
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The direct observations of some MBE grown superlattices show large interfacial undulations, which is attributed to the elastic relaxation of tensile layers. Assuming that the interface lateral lattice deformation, due to ionic radii misfit, is given by the periodic solution of the Frenkel-Kontorova model, we calculate the magnetoelastic contribution to the biquadratic magnetic coupling between ferromagnetic layers across the nonmagnetic spacer. We show that due to the correlated modulations of the effective bilinear exchange integral, there arises a biquadratic exchange which favours perpendicular orientations of magnetization in adjacent ferromagnetic layers.
DOI: 10.12693/APhysPolA.89.421
PACS numbers: 75.70.Cn, 75.70.Fr