Influences of compressive stress on the narrow hysteresis and piezomagnetic coefficient for the <110> oriented Tb_{0.27} Dy_{0.73} Fe_{1.95} alloys at high drive levels

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In this paper, the influences of compressive stress on the narrow hysteresis (magnetostriction hysteresis, W_h ) and maximum piezomagnetic coefficient ( d_{33}^{Max} ) of the <110> oriented Tb _{0.27} Dy _{0.73} Fe _{1.95} polycrystalline alloys have been investigated at high drive levels. The simultaneous measurements of magnetostriction and magnetization are carried out as a function of applied magnetic field 0 < H < 800 kA/m and compressive stress 0 to 50 MPa. The results show that the magnetostriction increases sharply in the low and/or moderate magnetic field, and than gains its saturation slowly with increase of the applied magnetic field. However, according to increase of the compressive stress, the magnetostriction decreases in the low and moderate magnetic field, while the saturation magnetostriction(λ _s ) increases. Specifically, λ _s increases from 1143 × 10 ^{ - 6} to 1778 × 10 ^{ - 6} when the compressive stress increases from 0 to 50 MPa and W_h increases from 7.90 to 27.22 kA/m at the same conditions. In addition, the characteristics of d_{33}^{Max} are reported under varied compressive stresses. It is found that the higher compressive stress the lower is d_{33}^{Max} , while at a fixed compressive stress, d_{33}^{Max} in the forward magnetostriction process is lower than that in the reversal magnetostriction process. These results presented are available for a kind of Tb-Dy-Fe alloys applications.