Synthesis, Structure, and Physical Properties of Ba$_{2}$Mn$_{2}$Sb$_{2}$O Single Crystals

We have grown high-quality single crystals of Ba$_{2}$Mn$_{2}$Sb$_{2}$O, which possesses the hexagonal structure as determined by X-ray powder diffraction technique. The magnetic susceptibility ($\chi )$ is isotropic above T$_{N }\sim $ 60 K, initially increasing with increasing temperature (T). After reaching the maximum at T$_{MAX} \quad \sim $ 150 K, $\chi $ decreases with increasing T and can be described by Curie-Weiss law with negative Curie-Weiss temperature. Below T$_{N}$, magnetic anisotropy is observed: $\chi _{ab}$ decreases sharply but $\chi _{c}$ increases with decreasing T, suggesting an antiferromagnetic type ordering at T$_{N}$. Interestingly, the temperature dependence of electrical resistivity along both \textit{ab} plane and $c$ direction changes from exponential dependence above T$_{MAX}$ to logarithmic dependence below T$_{MAX}$, reflecting strong Kondo effect.