The superconductive and magnetic properties of charge$-$compensated (Ca$_x$La$_{ 1-x}$)(Ba$_{ 1.75-x}$La$_{ 0.25+x}$)Cu$_3$O$_y$ (normally denoted as CLBLCO) are considered through quantitative examination of data for electrical resistivity, magnetic susceptibility, transition width, muon$-$spin rotation, x$-$ray absorption, and crystal structure. A derivative of LaBa$_2$Cu$_3$O$_y$, cation doping of this unique tetragonal cuprate is constrained by compensating La substitution for Ba with Ca substitution for La, where for 0 { \le} x { \le} 0.5 local maxima in T$_C$ occur for y near 7.15. It is shown that optimum superconductivity occurs for 0.4 { \le} x { \le} 0.5, that the superconductivity and magnetism observed are nonsymbiotic phenomena, and that charge$-$compensated doping leaves the carrier density in the cuprate planes nearly invariant with x, implying that only a small fraction of superconducting condensate resides therein. Applying a model of electronic interactions between physically separated charges in adjacent layers, the mean in-plane spacing between interacting charges, { \ell} = 7.1206 { \AA}, and the distance between interacting layers, { \zeta} = 2.1297 { \AA}, are determined for x = 0.45. The theoretical optimal T$_{ C0}$ { \propto} { \ell}$^{ -1}${ \zeta}$^{ -1}$ of 82.3 K is in excellent agreement with experiment ({ \approx} 80.5 K), bringing the number of compounds for which T$_{ C0}$ is accurately predicted to 37 from six different superconductor families (overall accuracy of { \pm}1.35 K).
Categories: cond-mat.supr-con