DOMAIN CONFIGURATIONS IN THE GIANT MAGNETOSTRICTIVE TBXHO1-XFE1.9 SYSTEM IN DIFFERENT EASY AXIS REGIMES

Domains have been observed in TbxHo1-xFe1.9 over the composition range 0 < x < 0.2 and temperature range - 10 to + 100-degrees-C, as a function of bias field. In the region where this system is [100] easy, the movement of {110} 90-degrees domain walls is shown to be responsible for the generation of negative magnetostrain, with increasing bias field. When [111] is easy, 71-degrees domain walls in {110} have been identified with a bias field applied. For x=0.1, at remanence, 180-degrees domain walls rotate smoothly with increasing temperature, from {100} when [100] is easy to {110} when [111] is easy. The presence of a bias field, at any temperature, brings out {110} walls which are 90-degrees walls in the [100] easy, low temperature, regime and 71-degrees walls in the [111] easy, high temperature, regime. At intermediate temperatures these walls remain in {110} with the magnetization in directions between [100] and [111]. These domain observations are shown to be consistent with theoretical magnetomechanical behavior based on a [1 uu], 0 < u < 1, transition in easy axis.