Magnetomechanical damping capacity of Tb_0.36Dy _0.64(Fe_1-xT_x)₂ (T=Co, Mn) alloys

The magnetomechanical damping capacity of the giant magnetostrictive Tb_0.36Dy_0.64(Fe_1-xT_x)₂ (x =0, 0.05, 0.10; T=Mn or Co) alloys has been calculated from quasistatic strain-stress hysteresis loops at room temperature. Stress ranges from 0 to 10, 20, 30, and 50 MPa were used in a series of applied fields between 0 and 3250 Oe. The largest damping capacities were obtained at zero field with values of 1.14 for Tb_0.36Dy_0.64Fe₂, 1.62 for Tb _0.36Dy_0.64(Fe_0.95Mn_0.05) ₂, and 1.84 for Tb_0.36Dy_0.64(Fe _0.90Co_0.10)₂, respectively. In low fields, the damping capacity ΔW/W decreases drastically with the applied stress and magnetic field. However, in higher fields, Δ W/W decreases slightly with the magnetic field but only increases slightly with the applied stress. The results show that both Mn and Co as substitutes for Fe are beneficial for obtaining higher damping capacity.