Magnetism and microstructure in epitaxial TbFe2 (111) thin films

We report the epitaxial growth of the highly magnetostrictive Laves phase compound TbFe2, oriented (1 1 1) on Mo (110) templates by means of molecular beam epitaxy. The film structure was investigated and related to the magnetic properties. Reflection high-energy electron diffraction showed the growth mode to be Stranski-Krastanov. Pronounced roughening was observed to follow strain relaxation, resulting in a film with deep grooves between islands. Differences of thermal expansion between the sapphire (11 (2) over bar 0) substrates and the magnetic epilayers place the films under tensile strain at room temperature and below. The magnetic properties of the films are analyzed as the magnetic response of single-domain particles subject to an anisotropic biaxial tensile strain. Dipolar domain coupling and in-plane strain anisotropy caused by the magnetostrictive distortion of domains are discussed for their relevance in explaining the anomalous magnetic hysteresis observed in these TbFe2 thin films. [50163-1829(98)00741-3].