S. Marinel et al., EFFECT OF SNO2 AND CEO2 DOPING ON THE MICROSTRUCTURE AND SUPERCONDUCTING PROPERTIES OF MELT-TEXTURED ZONE YBA2CU3O7-DELTA, Superconductor science and technology, 11(6), 1998, pp. 563-572
The microwave melt textured growth process (MMTG) is used to investiga
te the influence of CeO2 and SnO2 doping and their combination with tw
o different Sn/Ce initial ratios on the YBa2Cu3O7-delta (Y123) growth
mechanism, microstructure and superconducting properties. It was shown
that the combination of 'CeO2 + SnO2' allows us to increase the Y123
crystal growth velocity compared with CeO2 used alone. Furthermore, th
is combination reduces the Y2BaCuO5 particle coarsening observed when
SnO2 doping is added alone. Secondary phase SEM observations show that
square submicrometric precipitates are homogeneously distributed in t
he matrix when 'CeO2 + SnO2' are used. Thus, the identified phase appe
ars to be a solid solution derived from the phase Ba2YSnO5.5:Ba-2 (Y2/
3-xCux)(Ce, Sn)(4/3)O6-delta. In this article, the initial Sn/Ce ratio
was found to be a crucial parameter that affects the matrix purity. I
n terms of superconducting properties, 'CeO2 + SnO2' doped samples exh
ibit the highest magnetic critical current density in zero field (55 k
A cm(-2)), even under 1 Tesla (25 kA cm(-2)), depending on the Sn/Ce r
atio. The superconducting properties are discussed in relation with th
e microstructure and the EDS analysis results.