Enhanced differential magnetostrictive response in annealed Terfenol‐D

Abstract

<p>The field and pressure dependencies of the magnetostriction of Tb_0.316Dy_0.684Fe_1.982 have been measured in a grain‐oriented rod after thermally annealing for 1 day at 850 °C and for 4 days at 950 °C in an argon atmosphere. The results of the heat treatment are a fivefold increase in the strain coefficient <em>d</em> ₃₃(=<em>d</em>λ/<em>dH</em>) and a 100% increase in the maximum strain (λ). There was also an increase in the λ‐vs‐<em>H</em>hysteresis. Under compressive uniaxial stress there was virtually no bulk change in magnetostrictive strain until the field exceeded a critical value which depended on the applied stress, for instance ∼12 kA/m under a stress of 6 MPa.</p>