Effects of substrate on the magnetic properties of epitaxial TbFe 2(111) films

The effects of substrate on the strains of epitaxial TbFe₂ (111) films, and consequently on the magnetization orientation, have been studied. Thermal strain from differential thermal contraction between substrates and the TbFe₂ films is considered to be the dominant factor in determining the film strain. Therefore, Al₂ O₃(112¯0), MgO(111), and CaF₂(111) substrates with an epitaxial W(110) buffer layer have been used to grow the TbFe₂ films. The magnetisation of the TbFe₂ films on the Al₂O₃ and MgO substrates with a tensile thermal strain is in the film plane, but that on the CaF₂ substrate with a compressive thermal strain is in the out-of-plane direction. An unknown soft magnetic material has been found at the interfacial region of the TbFe₂ film and the W buffer layer