Title :
A new metastable phase with Tc of 32 K in La2CuO4+δ system
Author :
Chen, Ling ; Dong, Cheng ; Che, Guangcan ; Zhou, Fang ; Huang, Yuzhen ; Zhao, Zhongxian
Author_Institution :
Inst. of Phys., Acad. Sinica, Beijing, China
fDate :
3/1/2001 12:00:00 AM
Abstract :
A metastable superconducting phase with Tc of 32 K and δ=0.084 in La2CuO4+δ system is reported in this paper. It is prepared by electrochemical oxidation for more than 2 months using a small constant current of 10 μA. Its structure and physical properties are studied by X-ray diffraction, magnetic susceptibility and resistance measurements. This phase (we call it β-phase) is different from the previously known one (we call it α-phase) that has the same Tc but 0⩽δ⩽0.055. After heat treatment at temperature T=80°C, the β-phase decomposes into two phases with Tc´s of ~17 K and ~30 K, respectively. This kind of behavior is similar to the phase with Tc of 45 K. Our study shows that Tc increases with the intercalation rate, and oxygen distribution is an important factor for controlling superconducting properties
Keywords :
X-ray diffraction; critical current density (superconductivity); high-temperature superconductors; lanthanum compounds; magnetic susceptibility; phase diagrams; superconducting transition temperature; 10 muA; 2 month; 32 K; La2CuO4+δ system; La2CuO4; X-ray diffraction; electrochemical oxidation; high temperature superconductor; intercalation rate; magnetic susceptibility; metastable phase; metastable superconducting phase; oxygen distribution; resistance measurements; small constant current; Electrical resistance measurement; High temperature superconductors; Laboratories; Magnetic field measurement; Magnetic properties; Magnetic susceptibility; Metastasis; Oxidation; Superconductivity; Telephony;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
