Large magnetostriction over a wide temperature range in a Nd0.2TbxDy0.8−xFe1.93 Laves compound

Abstract

Rare-earth-based magnetostrictive alloys exhibit giant low-field magnetostriction due to anisotropy compensation at specific compositions and temperatures. However, the normally strong temperature dependency of magnetostriction is a common issue that limits its application temperature range. Here, we found that low-field magnetostrictive properties were optimized over a wide temperature range in a low-cost Nd0.2Tb xDy0.8− xFe1.93 system. A 140 K temperature window with λ ≥ 750 ppm at 2 kOe was achieved in the Nd0.2Tb0.3Dy0.5Fe1.93 compound, which is about 2.7 times wider than that in the well-known Terfenol-D composition. The construction of the Nd0.2Tb xDy0.8− xFe1.93 spin reorientation phase diagram revealed a slightly steeper slope of the phase boundary than that of the Nd-free system. Further analysis shows that a steep phase boundary allows the optimized composition to maintain low magnetocrystalline anisotropy and, thus, large low-field magnetostriction in a wide temperature range. The findings in this work may provide a route for designing wide-temperature-operating magnetostrictive materials by searching the phase boundary with a steep slope.