Investigation of the Phase Formation and Structure of TbCo₂ Cubic Laves Phase after Doping with Indium Atoms

The X-ray Rietveld method has been used to refine the structure, determine the lattice periods, and study the phase composition of the samples of multicomponent polycrystalline solid solutions TbCo \(_{{(2-x)}}\) In_x (х = 0, 0.05, 0.1, 0.15, 0.20, 0.25, 0.3, 0.35, 0.4), which are characterized by large values of magnetostriction saturation. With an increase in the indium concentration, the content of the TbCo₂ phase with a Laves phase structure decreases, the content of the TbCo₃ phase increases, and a Tb₁₁Co₄In₉ phase is formed. The lattice period in the TbCo₂ compound (sp. gr. Fd \(\bar {3}\) m) changes nonlinearly: increases in the range of x = 0–0.1 from a = 7.209(8) Å to a = 7.216(1) Å due to the replacement of cobalt atoms with indium atoms, having a larger radius. Then, in the concentration range of x = 0.15–0.4, it decreases to a = 7.205(1) Å at х = 0.4 due to the replacement of terbium atoms with indium and formation of structural defects.