Atomic scale study of negative thermal expansion in zirconium tungstate

Abstract

Perturbed angular correlation study in Zirconium tungstate shows the occurrence of four distinct Zr sites. Based on the values of quadrupole parameters, it is interpreted that one site represents regular ZrO₆ and the other three sites are associated with contracted and distorted ZrO₆. Effective decrease in Zr-O bond length is understood to be due to an increase in the fractions of ZrO₆ octahedra which undergo contraction with temperature, thus explaining negative thermal expansion of the system.