Magnetic and transport properties of RCr0.3Ge2 (R=Tb, Dy, Ho and Er) compounds

The magnetic and transport properties of ternary rare-earth chromium germanides R Cr0.3Ge2 (R =Y and Tb–Er) have been determined. X-ray and neutron diffraction studies indicate that these compounds have the CeNiSi2-type structure (space group Cmcm ) [1]. Magnetic measurements reveal the antiferromagnetic ordering below T N equal to 18.5 K (R =Tb), 11.8 K (Dy), 5.8 K (Ho) and 3.4 K (Er). From the neutron diffraction data the magnetic structures have been determined. For TbCr0.3Ge2 and DyCr0.3Ge2 at low temperatures the magnetic ordering can be described by two vectors k1=(View the MathML source12,0,0) and k2=(View the MathML source14,0,View the MathML source14), and k1′=(View the MathML source12,0,0) and k2′=(View the MathML source12,0,View the MathML source12), respectively. In HoCr0.3Ge2 and ErCr0.3Ge2 the ordering can be described by one propagation vector equal to (View the MathML source12,View the MathML source12,0) and (0,0,0.4187(2)), respectively. In DyCr0.3Ge2 some change in the magnetic ordering is observed at T t=5.1 K. In temperature range from T t to T N the magnetic ordering is given by one propagation vector k=(View the MathML source12,0,0). YCr0.3Ge2 is a Pauli paramagnet down to 1.72 K which suggests that in the entire RCr0.3Ge2 series the Cr atoms do not carry magnetic moments. All compounds studied exhibit metallic character of the electrical conductivity. The temperature dependencies of the lattice parameters reveal strong magnetostriction effect at the respective Nèel temperatures.