Tj. Yang et L. Horng, CORRELATION BETWEEN THE SUPERCONDUCTING TRANSITION-TEMPERATURE AND MADELUNG SITE POTENTIAL DIFFERENCE IN YBA2CU3OX, Physica. B, Condensed matter, 194, 1994, pp. 2149-2150
The Madelung site potentials have been calculated in YBa2Cu3Ox system
in order to find the role of the difference in the Madelung site poten
tials DELTAV(T) and DELTAV(M) within the ionic model. The bond valence
sum of each of the ions in the YBa2Cu3Ox compound is assigned as char
ge of the corresponding ion in the calculation of the Madelung site po
tential. Correlations between DELTAV = 0.75 DELTAV(M) +0.25 DELTAV(T)
obtained and superconducting transition temperature T(c) are examined
and found qualitatively very good agreement with the well-know experim
ental result for the various oxygen content x. This also supports that
the usual believing DELTAV(M) is of primary important parameter to co
ntrol T(c). The reason will be argrued in this paper.