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RESEARCH PRODUCT

Magnetic and magnetoelastic properties of epitaxial (2 1 1)-oriented RFe2 (R=Dy, Tb) thin films

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Abstract Epitaxial, (2 1 1)-oriented thin films of RFe 2 (R: rare earth; here: Dy, Tb) were deposited by molecular beam epitaxy on faceted and non-faceted α - Al 2 O 3 ( 1 0 1 ¯ 0 ) (m-plane) substrates utilizing a 15 A thin Fe seed layer and a 500 A Nb buffer layer. Detailed X-ray diffraction analyses revealed a twin-free epitaxial (2 1 1)-oriented growth of buffer layer and film. The magnetostrictive layer RFe 2 , as well as the template layers Nb and Mo exhibited the same crystallographic in-plane orientation with regard to the substrate. The same epitaxial relationship was found for films prepared on faceted and on non-faceted substrates. This implies a coherent crystal overgrowth of the epilayers over the facet ridges. Magnetization measurements of the RFe 2 films revealed coercive fields of 0.4 T for TbFe 2 and 0.13 T for DyFe 2 . The magnetoelastic coefficients at 1.1 T amounted to b = - 107 MPa and b = - 37 MPa for the TbFe 2 and DyFe 2 thin films, respectively.