Superconductivity in the Ag-substituted La<sub>1.8</sub>Sr<sub>0.2</sub>CuO<sub>4</sub> oxide system
S K Malik; C V Tomy; A M Umarji; D T Adroja; Ram Prasad; N C Soni; A Mohan; C K Gupta; S K Malik; Tata Inst. of Fundamental Res., Bombay, India; C V Tomy; Tata Inst. of Fundamental Res., Bombay, India; A M Umarji; Tata Inst. of Fundamental Res., Bombay, India; D T Adroja; Tata Inst. of Fundamental Res., Bombay, India; Ram Prasad; Tata Inst. of Fundamental Res., Bombay, India; N C Soni; Tata Inst. of Fundamental Res., Bombay, India; A Mohan; Tata Inst. of Fundamental Res., Bombay, India; C K Gupta; Tata Inst. of Fundamental Res., Bombay, India
Журнал:
Journal of Physics C: Solid State Physics
Дата:
1987-07-10
Аннотация:
The presence of mixed-valent copper and the nearly two-dimensional character of the K<sub>2</sub>NiF<sub>4</sub> structure are considered important for the occurrence of superconductivity in La<sub>1.8</sub>Sr<sub>0.2</sub>CuO<sub>4</sub> (T<sub>c</sub> onset 36 K). The authors have investigated the effect of partial replacement of mixed-valent Cu by monovalent Ag on the superconductivity of this system by studying the compositions La<sub>1.8</sub>Sr<sub>0.2</sub>Cu<sub>1-x</sub>Ag<sub>x</sub>O<sub>4</sub> (0.0<or=x<or=0.15). All these have the tetragonal K<sub>2</sub>NiF<sub>4</sub>-type structure. In spite of the charge imbalance caused by Ag substitution, the T<sub>c</sub> is found to decrease rather gradually from 36 K for x=0.0 to 20 K for x=0.15. A small increase in the Pauli susceptibility is also observed on partial replacement of Cu by Ag in the above system.
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