The stress dependence of k/sub 33/, d/sub 33/, lambda and mu in Tb/sub 0.3/Dy/sub 0.7/Fe/sub 1.95/

DC field measurements of lambda , d/sub 33/, k/sub 33/, and mu under uniaxial prestresses up to approximately 20 MPa have made on a 152-mm-long 6-mm-diameter grain-oriented rod of Tb/sub 0.3/Dy/sub 07/Fe/sub 1.95/ prepared by a free float zone technique. The lambda -vs.-H curve shows a negative dip at low fields which persist to approximately 20 MPa. The maximum negative strains approximately -120 ppm occur under approximately 2 MPa, which is also the pressure at which optimum permeability and magnetomechanical coupling occur. The origin of the negative strains is discussed in the light of earlier predictions based on an anisotropic rotational model for magnetization and magnetostriction, and the practical consequences are examined.>