Magnetoelastic coupling in TbFe2 (110) thin films

We have determined the rhombohedral magnetoelastic stress of a Laves phase TbFe2 (110) single-crystal film, grown by molecular-beam epitaxy. The film thickness was 1300 Angstrom. The magnetoelastic stress was directly measured by using a low-temperature cantilever capacitive method, between 300 and 10 K. The isotherms clearly display the coercive field but, unlike bulk alloy behavior, do not saturate even at the maximum field of 12 T. The determined rhombohedral magnetoelastic parameter of the film is Bε,2=-0.43 GPa, at 0 K and 12 T, which is 0.67 times the value for bulk TbFe2. Bε,2 follows a power m3 of the reduced magnetization m, indicating a single-ion volume origin for the rhombohedral magnetoelastic stress of this film. Measurements performed in a 300 Angstrom TbFe2 (110) film deposited onto a YFe2 buffer show that the coercive field is drastically lowered and that the magnetoelastic distortion is negligible. copyright 1997 American Institute of Physics