Multiple magnetic transitions in the spin-$\frac12$ chain antiferromagnet SrCuTe2O6

TL;DR

This study investigates the magnetic properties of SrCuTe2O6, revealing quasi-one-dimensional behavior above 7 K and two magnetic transitions below 5 K, driven by complex exchange interactions and frustration.

Contribution

It provides the first detailed analysis of SrCuTe2O6's magnetic behavior, highlighting the role of third-neighbor couplings and frustration in its low-temperature transitions.

Findings

Magnetic susceptibility follows a spin-chain model above 7 K.

Two magnetic transitions occur below 5 K.

Field-dependent phase diagram of transitions is characterized.

Abstract

Using thermodynamic measurements and density-functional band-structure calculations, we explore magnetic behavior of SrCuTe2O6. Despite being a structural sibling of a three-dimensional frustrated system PbCuTe2O6, this spin-1/2 quantum magnet shows remarkably different low-temperature behavior. Above 7 K, magnetic susceptibility of SrCuTe2O6 follows the spin-chain model with the antiferromagnetic intrachain coupling of J = 49.3 K. We ascribe this quasi-one-dimensional behavior to the leading third-neighbor coupling that involves a weakly bent Cu--O......O--Cu superexchange pathway with a short O.....O contact of 2.79 \AA. Below 5 K, SrCuTe2O6 undergoes two consecutive magnetic transitions that may be triggered by the frustrated nature of interchain couplings. Field dependence of the magnetic transitions (phase diagram) is reported.