High-pressure synthesis and properties of the Eu-substituted Ba8−xEuxSi46 clathrates

There has been considerable interest in rare-earth doped silicon clathrate compounds in order to understand the relation between the 4f electron moment and superconductivity. The Eu-doped silicon clathrates Ba8−xEuxSi46 (x=0, 0.5 and 1) were synthesized by using high-temperature and high-pressure. Structure characterization and magnetic measurement show Eu atoms enter clathrate lattice to occupy Ba positions. X-ray powder diffraction data indicate that the cubic lattice parameter a decreases with Eu doping. The magnetic measurements for all samples were studied. The incorporation of magnetic Eu2+ into the lattice suppresses the superconductivity completely and induces the Curie-paramagnetic behavior at high temperature. The influences of Eu2+ magnetic moment on the properties of samples were discussed.