Zn, Ce, Pr, and Th doping in YBa2Cu4O8.

Abstract

Computer-simulation techniques have been used to study Zn, Ce, Pr, and Th doping in ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$. Our results suggest that Zn energetically prefers to substitute at the Cu(2) site whereas Pr and Th prefer to substitute at the Y site. These results are in agreement with the experimental results. Our results also suggest that Ce preferentially substitutes for the Cu(2) site. The changes in interatomic distances caused by Zn, Ce, Th, and Pr doping were also presented and analyzed. Our calculated changes in lattice parameters of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{4}$${\mathrm{O}}_{8}$ due to Th and Ce doping are in qualitative agreement with the experimental results.