Synthesis methods and characterization of (Hg,Re)-1201

A. SERQUIS; L. MORALES; A. CANEIRO; A. BASSET; J.P. HODGES; J.D. JORGENSEN

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2001 vol. 349 p. 305 - 316

0921-4526

We analyze the in¯uence of the preparation method and Re content on the chemical stability, thermodynamicproperties and superconducting response of Hg1ÿxRexBa2CuO4‡d …0 < x < 0:2† samples. The route of synthesis is alsoinvestigated to optimize the incorporation of Re in the Hg-1201 structure. The samples are characterized by X-raydi€raction, scanning electron microscopy and microanalysis, and the in¯uence of Re content on the oxygen stoichiometryis studied by means of thermogravimetry. The superconducting response of samples and their aging are studiedby d.c. susceptibility. We ®nd that Re doping increases the thermodynamic stability due to the incorporation of highlybonded oxygen atoms in the (Hg,Re)±Od planes. In addition, Re-free samples prepared with Hg excess remain stable forlong periods under ambient atmosphere. An optimal synthesis method and the Hg excess would avoid the formation ofamorphous phases composed of Ba and Cu oxides which are responsible of such degradation in samples with Hgde®ciency.