Crystal structure and electrical properties of the new R2TSi2 compounds (R = rare earths; T = Fe, Co)

Abstract The R 2 FeSi 2 compounds with R=Gd, Tb, Dy, Ho, Er, Tm, Y, and R 2 CoSi 2 with R=Ho, Er, Tm, were synthesized and studied by X-ray powder diffraction. All phases crystallize in the Sc 2 CoSi 2 monoclinic structure type, and the atomic positional and thermal parameters were refined by single crystal data for Tb 2 FeSi 2 , Er 2 FeSi 2 and Er 2 CoSi 2 . The measurement of the electrical resistance in the 13–300 K temperature range showed for all phases, save the yttrium compounds, a transition point which indicates an order–disorder magnetic change. The scaling of these temperatures with the de Gennes factor gives a good correlation, with some slight deviations probably due to crystal electric field effects.