Physical Properties of $B{a}_{2}M{n}_{2}S{b}_{2}O$ Single Crystals

Abstract

We report both experimental and theoretical investigations of the physical properties of Ba${}_2$Mn${}_2$Sb${}_2$O single crystals. This material exhibits a hexagonal structure with lattice constants: a = 4.7029(15) à and c = 19.9401(27) à , 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$$\hat{\mathrm{I}}{˜}_{\mathrm{CW}}$$\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.

6 Pages, 5 Figures, and 1 Table