Magnetostriction and thermal expansion of nonstoichiometric TbCo2Mnx compounds

Abstract The magnetostriction and thermal expansion of the TbCo2Mnx compounds (0 ≤ x ≤ 0.6) have been investigated. The compounds crystallize in the cubic MgCu2-type lattice in spite of the Tb to 3d-metal (Co + Mn) ratio deviates from the stoichiometry. The spontaneous and forced volume magnetostriction as well as anisotropic magnetostriction were determined for various temperatures. The intra- and intersublattice Tb-Tb, Tb-3d and 3d-3d exchange interactions were estimated within the molecular field model for a two-sublattice ferrimagnet. It was found that the compounds have a large volume and anisotropic magnetostriction in a wide temperature range. At room temperature, TbCo2Mn0.4 compound possesses high linear magnetostriction of 400 ppm in magnetic field of 5 kOe, which makes it possible to consider the nonstoichiometric compounds as promising materials for magnetostrictive applications.