Revival of superconductivity in Y<sub>0.4</sub>Pr<sub>0.6</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7- delta </sub> by the isovalent substitution of Sr
Guanghan Cao; Yitai Qian; Xiaojun Li; Zuyao Chen; Chengyou Wang; Keqing Ruan; Yiming Qiu; Liezhao Cao; Yuan Ge; Yuheng Zhang; Guanghan Cao; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Yitai Qian; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Xiaojun Li; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Zuyao Chen; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Chengyou Wang; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Keqing Ruan; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Yiming Qiu; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Liezhao Cao; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Yuan Ge; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China; Yuheng Zhang; Dept. of Appl. Chem., Univ. of Sci. & Technol. of China, Hefei, China
Журнал:
Journal of Physics: Condensed Matter
Дата:
1995-06-05
Аннотация:
Polycrystalline samples of Y<sub>0.4</sub>Pr<sub>0.6</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7- delta </sub> have been prepared and characterized by X-ray powder diffraction, differential thermal analysis and temperature dependence of resistivity and AC susceptibility. We observed that both superconductivity and metallic conductivity were revived at x>or=0.75, accompanied by an orthorhombic-to-tetragonal transition. The superconducting transition temperature could be further enhanced by increasing the Sr content, suggesting that there is an ion-size effect on T<sub>c</sub> at the Ba site. The results were discussed in terms of the Pr-O covalent bonding effect.
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