MAGNETISM AND MICROSTRUCTURE IN EPITAXIAL TBFE2 (111) THIN-FILMS

We report the epitaxial growth of the highly magnetostrictive Laves ph ase compound TbFe2, oriented (1 1 1) on Mo (110) templates by means of molecular beam epitaxy. The film structure was investigated and relat ed to the magnetic properties. Reflection high-energy electron diffrac tion showed the growth mode to be Stranski-Krastanov. Pronounced rough ening was observed to follow strain relaxation, resulting in a film wi th deep grooves between islands. Differences of thermal expansion betw een the sapphire (11 (2) over bar 0) substrates and the magnetic epila yers place the films under tensile strain at room temperature and belo w. The magnetic properties of the films are analyzed as the magnetic r esponse of single-domain particles subject to an anisotropic biaxial t ensile 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 obser ved in these TbFe2 thin films. [50163-1829(98)00741-3].