Ion Substitution Effects on the Structure Stability of Cuprate Superconductors

M.K. Wu; D.H. Chen; D.Y. Chen; S.R. Sheen; F.Z. Chien

doi:10.6180/jase.2000.3.3.03

Ion Substitution Effects on the Structure Stability of Cuprate Superconductors

$Observed and calculate powder x-ray diffraction pattern of YSr2Cu2.8Mo0.2O6.97.$

M. K. Wu¹ , D. H. Chen¹ , D. Y. Chen¹ , S. R. Sheen¹ and F. Z. Chien²

¹Materials Science Center, National Tsing Hua University, Hsinchu, Taiwan ROC
²Department of Physics, Tamkang University, Tamsui, Taipei, Taiwan ROC

Received: March 1, 2000
Accepted: September 1, 2000
Publication Date: September 1, 2000

Download Citation: ||https://doi.org/10.6180/jase.2000.3.3.03

ABSTRACT

We have demonstrated that using a transition metal ion to partially substitute Cu ion of the YSr₂Cu₃O_y can stabilize its crystal structure and retain superconductivity. The superconducting transition temperature in YSr₂(Cu_1-xM_x)₃O_y, where M is transition metal ion, ranges from 40K to 80K depending on the specific M ion. Lattice contraction due to Sr substitution makes the Ba/Sr ion to move closer to CuO plane, and consequently leads to a charge transfer between oxygen. Our study shows that the key factor controlling the structural stability in Y-Sr-Cu-O system is the effective ionic radius Sr in lattice. The introduction of transition metal doping is to increase the effective ionic radius of Sr through the increase of oxygen content.

Keywords: superconductivity; lattice parameters; perovskite; tolerance factor

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