Abstract
We report on the magnetic and structural characterization of high lattice-mismatched [Dy/Sc] superlattices, with variable Sc thickness = 2–6 nm. We find that the characteristic in-plane effective hexagonal magnetic anisotropy K reverses sign and undergoes a dramatic reduction, attaining values of 13–24 kJm, when compared to K MJm in bulk Dy. As a result, the basal plane magnetic anisotropy is dominated by a uniaxial magnetic anisotropy (UMA) unfound in bulk Dy, which amounts to 175–142 kJm. We attribute the large downsizing in K to the compression epitaxial strain, which generates a competing sixfold magnetoelastic (MEL) contribution to the magnetocrystalline (strain-free) magnetic anisotropy. Our study proves that the in-plane UMA is caused by the coupling between a giant symmetry-breaking MEL constant M GPa and a morphic orthorhombiclike strain , whose origin resides on the arising of an in-plane anisotropic strain relaxation process of the pseudoepitaxial registry between the nonmagnetic bottom layers in the superstructure. This investigation shows a broader perspective on the crucial role played by epitaxial strains at engineering the magnetic anisotropy in multilayers.
5 More- Received 25 November 2013
- Revised 17 February 2014
DOI:https://doi.org/10.1103/PhysRevB.89.134421
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