Magnetic properties and magnetic structure of the frustrated quasi-one-dimensional antiferromagnet SrCuTe$_2$O$_6$

TL;DR

This study investigates the magnetic properties and structure of SrCuTe$_2$O$_6$, revealing weak anisotropy, a dominant third-nearest-neighbor exchange interaction, and a complex antiferromagnetic order influenced by frustration.

Contribution

The paper provides detailed experimental and theoretical analysis of the magnetic structure and interactions in SrCuTe$_2$O$_6$, highlighting the role of frustration and identifying the magnetic ordering pattern.

Findings

Weak magnetic anisotropy observed in magnetization measurements.

Dominant third-nearest-neighbor exchange interaction with $J_3/k_B$ around 50-52 K.

Magnetic ordering occurs below 5.25 K with a reduced ordered moment of 0.52 μ_B.

Abstract

Magnetization measurements on single-crystal cubic SrCuTe$_2$O$_6$ with an applied magnetic field of along three inequivalent high symmetry directions $[100]$, $[110]$, and $[111]$ reveal weak magnetic anisotropy. The fits of the magnetic susceptibility to the result from a quantum Monte Carlo simulation on the Heisenberg spin-chain model, where the chain is formed via the dominant third-nearest-neighbor exchange interaction $J_3$, yield the intra-chain interaction $(J_3/k_B)$ between 50.12(7) K for the applied field along $[110]$ and 52.5(2) K along $[100]$ with about the same $g$-factor of 2.2. Single-crystal neutron diffraction unveils the transition to the magnetic ordered state as evidenced by the onset of the magnetic Bragg intensity at $T_\textrm{N1}=5.25(9)$ K with no anomaly of the second transition at $T_\textrm{N2}$ reported previously. Based on irreducible representation theory and magnetic space group analysis of powder and single-crystal neutron diffraction data, the magnetic structure in the Shubnikov space group $P4_132$, where the Cu$^{2+}$~$S=1/2$ spins antiferromagnetically align in the direction perpendicular to the spin chain, is proposed. The measured ordered moment of $0.52(6)~\mu_B$, which represents 48% reduction from the expected value of $1~\mu_B$, suggests the remaining influence of frustration resulting from the $J_1$ and $J_2$ bonds.