Horiacha M. Influence of component substitution on the crystal structure and properties of the RETIn and RETIn2 (RE = Y, Gd, Tb; T = Ni, Cu) compounds

By means of X-ray phase and local energy-dispersive X-ray spectroscopy the phase composition of the alloys and the crystal structures of the phases were determined. The interaction of components in systems: RETIn1-xAlx (RE = Y, Gd, Tb; T = Ni, Cu), RETIn1-xGax (RE = Y, Gd, Tb; T = Ni, Cu), RENiIn1-xGex (RE = Gd, Tb), RENiIn1-xSbx (RE = Y, Gd, Tb), RECuIn1-xSbx (RE = Gd), RECuIn1-xSix (RE = Y), RENiIn2-xAlx (RE = Y, Gd, Tb), RENiIn2-xGax (RE = Y, Gd, Tb), RENiIn2-xSbx (RE = Gd), RENiM4-xInx (RE = Y, Gd, Tb; M = Al, Ga) were determined. The formation of continuous solid solutions with ZrNiAl-type structure was establish in six systems RETIn1-xAlx (RE = Y, Gd, Tb; T = Ni, Cu), by substitution of indium by aluminium. Others systems are characterized by limited solubility of the fourth component. Within the limits of the existence of solid solutions crystal structures of seven compounds were investigated by means of X-ray powder diffraction, crystal structure of twenty seven compounds were refined from the single-crystal X-ray diffraction data. Substitution of the p-element in compounds with MgCuAl2 type structure has been found much more complex and in some cases lead to the structure transformation. The peculiarities of the components interaction in the investigated systems were discussed. For the first time, the existence of 22 quaternary RENi2Ga3In (RE = Y, Gd-Tm), REPt2Ga3In (RE = Y, Gd-Yb), RE2Pt3Ga4In (RE =Y, Gd-Yb) compounds, that crystallize in GdNi2Ga3In, NdRh2Sn4 and Y2Rh3Sn5 structure types, respectively, were established. The structures of the new compounds are characterized by trigonal-prismatic coordination of smaller atoms. On the basis of the results of measurements of the magnetic properties, it was determined: the phases of the YNiIn1-xAlx solid solution are typical Pauli paramagnet and rare-earth element in the samples of TbNiIn1-xGax system has a stable Tb3+ state. The YNi2Ga3In compound is a paramagnet, and the RENi2Ga3In (RE = Dy, Ho), GdPt2Ga3In, RE2Pt3Ga4In (RE = Gd, Tb) compounds are characterizes by antiferromagnetic ordering.