In-situ studies of low-field large magnetostriction in Tb_1-xDy_xFe₂ compounds by synchrotron-based high-energy x-ray diffraction

Partial substitution of Dy for Tb in TbFe₂ compounds results in improved magnetostriction with high strains obtained at low fields. The structural evolutions of TbFe₂ and Tb_0.4Dy_0.6Fe₂ compounds are studied in situ using synchrotron-based high-energy x-ray diffraction under an applied magnetic field. It is found that the rhombohedral distortion in TbFe₂ is remarkably reduced by substituting Dy for Tb. When a low magnetic field is applied, a preferential rearrangement of rhombohedral domains is directly evidenced in TbFe₂ and Tb_0.4Dy_0.6Fe₂ compounds. Based on the concept of crystallographic domain-switching, the enhancement in the magnetostriction in Tb_1-xDy_xFe₂ compounds is discussed.