Publication
Journal of Applied Physics
Paper

Synchrotron x-ray diffraction studies of the lattice and magnetic structure of epitaxial Dy films in LaF3/Dy/LaF3 sandwiches

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Abstract

Lattice and magnetic x-ray diffraction from a 2000 Å thick film of Dy, sandwiched by LaF3 films on a GaAs(111) substrate, are reported. The structure was grown by molecular beam epitaxy with the c axis of the Dy parallel to the LaF3 c axis and GaAs [111] axis. We find that the c-axis lattice constant of the Dy has a similar temperature dependence to bulk Dy from room temperature to about 110 K, but below this, the film is different from bulk. The transition to ferromagnetic ordering at ∼86 K exhibits temperature hysteresis which is also evident in the magnetic x-ray scattering and SQUID magnetometry data. This hysteresis may arise from a combination of the strain-energy barrier accompanying the transition and magnetic inhomogeneities in the film. The temperature dependence of the magnetic wave vector is qualitatively similar to bulk, although a weaker dependence is observed below ∼110 K, which is possibly caused by magnetoelastic effects. The magnetic coherence length (310 Å) is significantly shorter than the structural coherence length (730 Å).

Date

01 Dec 1991

Publication

Journal of Applied Physics

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