Physical properties of polycrystalline Dy2PdGe6 and La2PdGe6

Polycrystalline samples of the intermetallic compounds Dy 2 PdGe 6 and La 2 PdGe 6 which crystallize in the orthorhombic structure ( Cmca space group) were studied by means of magnetic, electrical resistivity, specific heat and differential thermoelectric power measurements. The Dy-germanide is an antiferromagnet below 25(1) K and at low temperature and above magnetic fields of 3.5 T it exhibits a metamagnetic behaviour. Especially the specific heat measurements point to well-localized 4 f -electrons in this compound. Whereas the isostructural La-germanide is a nonmagnetic material taken here as a reference compound. A good overall fit of the resistivity to a general Bloch–Gruneisen formula indicates its metallic character in contrast to the Dy-germanide being a semimetallic-like conductor. For the latter compound in its ordered state the electrical resistvity, specific heat and thermoelectric power are dominated by electron–magnon scattering with antiferromagnetic spin-wave spectrum typical of anisotropic antiferromagnetic systems. The observed Schottky anomaly yields an assumed crystal field scheme of low-energy lying levels. Its thermoelectric power behaviour achieves medium positive values at high temperatures, indicating a hole domination in electrical transport properties. On the other hand, S ( T ) below T N for Dy- and in the whole temperatures measured for La-based compounds is negative, pointing to their electron carrier origin.