THE SYNTHESIS AND CHARACTERIZATION OF THE SUPERCONDUCTOR-RELATED COMPOUND PB2SR2AMCU3O8

A new member of the superconducting series Pb2Sr2(R/Ca)Cu3O8 has been synthesized with R=Am (Z=95). X-ray diffraction, Am L(3)-edge X-ray ab sorption spectroscopy, and magnetic susceptibility data were used to c haracterize the sample. This actinide analog has a structure similar t o the other members of the series, but it could not be made supercondu cting. Am L(3)-edge X-ray absorption near edge structure (XANES) and e xtended X-ray absorption fine structure (EXAFS) are used to show that Am is tetravalent in Pb2Sr2(Am/Ca)CU3O8, a finding supported by the su sceptibility data. The absence of superconductivity in this Am analog of the Pb-based system is discussed in terms of the presence of a tetr avalent R-ion and the resulting charge compensation.