The influence of Zn$^{2+}$ ions on the local structure and thermochromic properties of Cu$_{1-x}$Zn$_x$MoO$_4$ solid solutions

TL;DR

This study investigates how Zn$^{2+}$ ions affect the local structure and thermochromic phase transitions in Cu$_{1-x}$Zn$_x$MoO$_4$ solid solutions using advanced spectroscopy and analysis techniques.

Contribution

It provides detailed local structural insights into Cu$_{1-x}$Zn$_x$MoO$_4$ solid solutions and reveals the impact of zinc substitution on thermochromic phase behavior.

Findings

Thermochromic phase transition observed in Cu$_{0.90}$Zn$_{0.10}$MoO$_4$ with hysteresis.

Local environment of molybdenum ions is highly affected by zinc substitution.

MoO$_4$ tetrahedral structure transforms to MoO$_6$ octahedral upon cooling.

Abstract

The influence of zinc ions on the thermochromic properties of polycrystalline Cu$_{1-x}$Zn$_x$MoO$_4$ ($x$=0.10, 0.50, 0.90) solid solutions was studied by X-ray absorption spectroscopy at the Cu, Zn and Mo K-edges. Detailed structural information on the local environment of metal ions was obtained from the simultaneous analysis of EXAFS spectra measured at three metal absorption edges using the reverse Monte Carlo method. Thermochromic phase transition with the hysteretic behaviour between $\alpha$ and $\gamma$ phases was observed in Cu$_{0.90}$Zn$_{0.10}$MoO$_4$ solid solution. It was found that the local environment of molybdenum ions is most susceptible to the substitution of copper for zinc and, upon cooling, transforms from tetrahedral MoO$_4$ to distorted octahedral MoO$_6$.