SPRAY DEPOSITED TL-BA-CA-CU-O FILMS AND BULKS SUBJECTED TO A COMMON ANNEAL

Superconducting TI-Ba-Ca-Cu-O (TBCCO) 2212 firms have been prepared by annealing the spray deposited precursor Ba-Ca-Cu-O/MgO layers with cr ude TBCCO pellets. Properties of both films and bulks are described. T o deposit the precursor films, an aerosol generated ultrasonically fro m aqueous nitrate solution was used. The prepared 2212 films were 2-3 mu m thick; the highest T-c=102 K was obtained in both film and pellet annealed at 850 degrees C for 30 min. The J(c) values measured on som e films were in the interval 10(3)-10(4) A cm(-2); the XRPD data show rather low grain orientation both in films and in bulks. The x-ray pat terns revealed that the film samples contain more than 95 vol.% of 221 2 phase; the bulks contain more than 90 vol.% of 2212. The AES depth p rofiles in the surface layers of films show a slight drop in the TI co ntent towards the film-substrate interface. From the Raman spectra, XR PD data, structural investigation and physical properties of obtained 2212 phases, correlations among cationic disorder, c axis parameters, T-c values and frequency of the Raman modes were deduced. Results of d etailed thermogravimetric TG, DTG and DTA measurements of homogenized precursor Ba-Ca-Cu nitrate and oxide mixtures as well as those of the crude TI-Ba-Ca-Cu oxide mixture are presented.