Solution Phase Synthesis of Superconducting La{sub}2CuO{sub}4 Microspheres

摘要

In order to exploit new strategies for fabricating high-temperature superconductors with special morphologies and investigate the effects on their superconductivity, we successfully utilized a facile polyol process for fabricating a large amount of La{sub}2CuO{sub}4 (LCO) microspheres using La(CH{sub}3COO){sub}3·1.5H{sub}2O and Cu(CH{sub}3COO){sub}2·H{sub}2O as raw materials and ethylene glycol as both complex agent and solvent. The well crystallized LCO microspheres can be obtained by annealing the La-Cu-complex precipitation formed after refluxing process at 750°C for 10 hours. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results indicated that the as-prepared sample had an average diameter of about 800nm. The powder X-ray diffraction (XRD) patterns showed that the LCO microspheres were of pure phase. The magnetization measurement of the sample annealed at 900°C in pure oxygen for 20 hours showed that the superconducting transition temperature (T{sub}c) of the LCO microspheres was about 38K, which in agreement with that of bulk counterparts.