Substitution in Ce2TSi3 intermetallic compositions with T=(Cr, Mn, Fe, Co, or Ni)(x)(Pd or Au)(1-x)

Alloys of composition Ce-2(3d/T)Si-3, with 3d one of Cr, Mn, Fe, Co or Ni and T being Pd or Au, were prepared and examined by powder X-ray diffraction. Select single phase compositions were further examined by magnetic susceptibility, by resistivity for the Pd and Co end-members, and by specific heat for Ce2CoSi3. For compounds not containing cobalt, effective cerium moments consistent with trivalent cerium were observed. A re-examination of the AlB2 related structure of Ce2CoSi3 by single crystal methods revealed ordering of cobalt within the CoSi3 hexagonal layer. Magnetic susceptibility, resistance and specific heat measurements suggest valence fluctuation behavior of the cerium in Ce2CoSi3. A return to trivalent cerium magnetic behavior occurs on increasing the palladium or gold substitution for cobalt.