CRYSTAL-STRUCTURE AND VALENCE BEHAVIOR OF YBPDXGA11-X

The ternary phase YbPdxGa11-x has been synthesized from the elements b y high frequency argon melting. An extended homogeneous region at 600 degrees C has been established from X-ray powder data for 2.3 less tha n or equal to x less than or equal to 3.4. The crystal structure of Yb Pd3Ga8 has been derived from X-ray single crystal counter data: partia lly ordered BaHg11-type, space group Pm3m(O-h(1), No. 221), a= 8.4346( 5)Angstrom:R-p = 0.054 for 176 independent reflections with I>2 sigma. YbPdxGa11-x samples are temperature independent Pauli-type paramagnet s for x less than or equal to 3. Increasing the palladium content to x >3 leads to an enhanced f-d electron interaction, and a variation of t he magnetic moment due to valence instabilities (4f(14)-->4f(13)) is e stablished using X-ray absorption spectroscopy.