Physical Properties of $Ba_2 Mn_2 Sb_2 O$ Single Crystals

TL;DR

This study combines experimental and theoretical methods to explore the structural, magnetic, and electronic properties of Ba2Mn2Sb2O single crystals, revealing antiferromagnetic order and complex resistivity behavior.

Contribution

It provides new insights into the magnetic and electronic properties of Ba2Mn2Sb2O, supported by DFT calculations and detailed experimental measurements.

Findings

Antiferromagnetic ordering at T_N = 60 K

Reduced dimensionality indicated by susceptibility and Curie-Weiss temperature

Resistivity transitions from activated to logarithmic behavior around 200 K

Abstract

We report both experimental and theoretical investigations of the physical properties of Ba$_\mathrm{2}$Mn$_\mathrm{2}$Sb$_\mathrm{2}$O single crystals. This material exhibits a hexagonal structure with lattice constants: a = 4.7029(15) \AA{} and c = 19.9401(27) \AA{}, as obtained from powder X-ray diffraction measurements, and in agreement with structural optimization through density functional theory (DFT) calculations. The magnetic susceptibility and specific heat show anomalies at T$_\mathrm{N}$ = 60 K, consistent with antiferromagnetic ordering. However, the magnitude of T$_\mathrm{N}$ is significantly smaller than the Curie-Weiss temperature ($\mid$$\mathrm{\Theta_{CW}}$$\mid$ $\approx$ 560 K), suggesting a magnetic system of reduced dimensionality. The temperature dependence of both the in-plane and out-of-plane resistivity changes from an activated at $T$ $>$ T$_\mathrm{x}$ $\sim$ 200 K to a logarithmic at $T$ $<$ T$_\mathrm{x}$. Correspondingly, the magnetic susceptibility displays a bump at T$_\mathrm{x}$. DFT calculations at the DFT + U level support the experimental observation of an antiferromagnetic ground state.