Magnetostriction drop in 〈110〉 oriented polycrystals Tb _0.36Dy_0.64(Fe_0.85Co_0.15) ₂ after transverse field annealing

A 110 oriented polycrystal Tb_0.36Dy_0.64(Fe _0.85Co_0.15)₂ was subjected to annealing in a transverse field of 240 kA/m. Axial magnetostrictions (defined as λ_∥) of the magnetically annealed specimen were investigated in fields applied at a series of angles θ away from its axis. For the untreated specimen, at the angle θ scope from 30° to 60°, λ_∥ increases to a maximum and then drops gradually during magnetization processes. After magnetic annealing, however, the magnetostriction drop behavior occurs at a narrower range from 40° to 60°. In addition, at these magnetization directions where drop occurs, is negative for the magnetically annealed specimen, whereas it keeps positive for the untreated one. The value of dropped magnetostriction (defined as | δλ_∥, d |) increases with the increase of for the untreated specimen, but decreases for the magnetically annealed one. Based on a single-{111}-twin crystal growth model, magnetic domain rotation paths are simulated to explain the differential magnetostriction drop behavior.