Solution Phase Synthesis of Superconducting La2CuO4 Microspheres
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 La2CuO4 (LCO) microspheres using La(CH3COO)3·1.5H2O and Cu(CH3COO)2·H2O 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 oC 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 800 nm. 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 oC in pure oxygen for 20 hours showed that the superconducting transition temperature (Tc) of the LCO microspheres was about 38 K, which in agreement with that of bulk counterparts.
Yafang Han et al.
G.Q. Zhang et al., "Solution Phase Synthesis of Superconducting La2CuO4 Microspheres", Materials Science Forum, Vols. 546-549, pp. 2071-2074, 2007