TY - JOUR
T1 - Superconducting La1.5-xBa1.5+x-yCayCu3Oz solid solutions I. Phase diagram, cation stoichiometry and Tc data
AU - Skakle, J. M S
AU - West, A. R.
PY - 1994/2/1
Y1 - 1994/2/1
N2 - The phase diagram for the LaBCCO solid solutions La1.5-xBa1.5+x-yCayCu3Oz has been determined in air at 950°C. Solid solution form over the complete composition range 0≤x≤0.5, 0≤y≤0.5 apart from composition at high x and low y, centred on the La-123 composition LaBa2Cu3Oz. The LaBCCO solid solutions are tetragonal at all oxygen contents and are structurally distinct from tetragonal/orthorhombic La-123, which can be prepared as a stoichiometric phase by reaction in Ar. Tc values of the LaBCCO solid solutions increase linearly with x at constant y and with y at constant x for samples prepared under the same conditions. Maximum Tc is ∼78 K for x=y=0.5 for samples that were oxygen annealed at 400°C. The melting behaviour of the LaBCCO solid solutions has been determined. Melting temperatures increase with both decreasing x and y; the La-336 composition has the highest melting temperature (∼1180°C) and melts incongruently to La2CuO4 + liquid.
AB - The phase diagram for the LaBCCO solid solutions La1.5-xBa1.5+x-yCayCu3Oz has been determined in air at 950°C. Solid solution form over the complete composition range 0≤x≤0.5, 0≤y≤0.5 apart from composition at high x and low y, centred on the La-123 composition LaBa2Cu3Oz. The LaBCCO solid solutions are tetragonal at all oxygen contents and are structurally distinct from tetragonal/orthorhombic La-123, which can be prepared as a stoichiometric phase by reaction in Ar. Tc values of the LaBCCO solid solutions increase linearly with x at constant y and with y at constant x for samples prepared under the same conditions. Maximum Tc is ∼78 K for x=y=0.5 for samples that were oxygen annealed at 400°C. The melting behaviour of the LaBCCO solid solutions has been determined. Melting temperatures increase with both decreasing x and y; the La-336 composition has the highest melting temperature (∼1180°C) and melts incongruently to La2CuO4 + liquid.
UR - http://www.scopus.com/inward/record.url?scp=0028378158&partnerID=8YFLogxK
U2 - 10.1016/0921-4534(94)90900-8
DO - 10.1016/0921-4534(94)90900-8
M3 - Article
AN - SCOPUS:0028378158
VL - 220
SP - 187
EP - 194
JO - Physica. C, Superconductivity
JF - Physica. C, Superconductivity
SN - 0921-4534
IS - 1-2
ER -