Low-dimensional magnetism of BaCuTe$_{2}$O$_{6}$

TL;DR

This study investigates the magnetic properties of BaCuTe$_{2}$O$_{6}$, revealing its low-dimensional spin-1/2 chain behavior, a single magnetic transition, and insensitivity to magnetic dilution, with comparisons to the Sr analog highlighting microscopic differences.

Contribution

The paper provides the first detailed analysis of BaCuTe$_{2}$O$_{6}$'s magnetic behavior, demonstrating its one-dimensional spin chain nature and the impact of chemical substitution on magnetic interactions.

Findings

BaCuTe$_{2}$O$_{6}$ exhibits one-dimensional spin-$rac{1}{2}$ Heisenberg chain behavior.

The Néel temperature increases from Sr to Ba compound despite reduced intrachain coupling.

Magnetic dilution with Zn$^{2+}$ has little effect on the Néel temperature.

Abstract

X-ray diffraction, thermodynamic measurements, and density-functional band-structure calculations are used to study the magnetic behavior of BaCuTe$_{2}$O$_{6}$, a member of the $A$CuTe$_2$O$_6$ structural family that hosts complex three-dimensional frustrated spin networks with possible spin-liquid physics. Temperature-dependent magnetic susceptibility and heat capacity of the Ba compound are well described by the one-dimensional spin-$\frac12$ Heisenberg chain model reminiscent of the Sr analog SrCuTe$_2$O$_6$. While the intrachain coupling $J/k_{\rm B}\simeq 37$ K is reduced compared to 49 K in the Sr compound, the N\'eel temperature increases from 5.5 K (Sr) to 6.1 K (Ba). Unlike the Sr compound, BaCuTe$_2$O$_6$ undergoes only one magnetic transition as a function of temperature and shows signatures of weak spin canting. We elucidate the microscopic difference between the Sr and Ba compounds and suggest that one of the interchain couplings changes sign as a result of negative pressure caused by the Sr/Ba substitution. The N\'eel temperature of BaCuTe$_2$O$_6$ is remarkably insensitive to the magnetic dilution with Zn$^{2+}$ up to the highest reachable level of about 20%.