Published online by Cambridge University Press: 03 March 2011
The preparation of thick films of the LaBa2Cu3Oy (La-123) phase by using the partial melting technique (PMT) of powders deposited on MgO substrates by drying alcoholic suspensions is reported. The effects of the starting composition, processing time (t), and temperature (T) on the superconducting properties of the La1+xBa2Cu3Oy (−0.25 ⋚ x ⋚ 0.5) system were investigated. The presence of the La4Ba2Cu2O10 (La 422) phase was detected in the samples quenched in liquid N2 after heating up to 1200 °C. The crucial step of the processing is the cooling rate down to the crystallization temperature, Tp, determined by DTA analysis, in order to favor the formation of the La-123 phase from the reaction between the La-422 solid phase and the liquid. The superconducting properties, tested by magnetization measurements, showed a diamagnetic onset temperature (Tc,diam) as high as 89 K.