Magnetoelastic stresses in epitaxial (110) Terfenol-D thin films

Abstract The magnetic and magnetoelastic (MEL) behaviour of single-crystal (1 1 0) Terfenol-D thin films, 600 and 1000 A thick, have been investigated by performing magnetization and MEL stress measurements between 12 and 290 K, up to 12 T. Magnetization isotherms were performed by applying the magnetic field within the growth plane of the samples. The magnetization is more easily saturated along [1 1 0] than along [1 1 1] at 290 K, contrarily to the bulk case. However, on decreasing the temperature, below 200 K, [0 0 1] is the easiest direction. Furthermore, the combination of different MEL stress measurements allowed us to determine the MEL stress parameters b 0 (associated to volume and tetragonal magnetostriction (MS)), b 1 (to tetragonal MS alone) and b 2 (to rhombohedral MS). The values of b 0 MEL stress parameters are negligible. The b 1 and b 2 values agree in sign with the respective bulk values; the order of magnitude of b 2 is the same as for the bulk, however, the b 1 MEL stresses are about three times larger. The thermal dependencies of b 2 and b 1 show a peak at around 50 K. The above facts indicate that non-linear volume terms and interfacial contributions play an important role in the MEL energy.