Abstract:
The thermal properties—specific heat, thermal conductivity, and thermal expansion coefficients—of a single crystal of quasi-one-dimensional variable-valence β-Na0.33V2O5 compound were studied. With lowering temperature, it sequentially undergoes the structural (TS∼ 230 K), charge (TC∼ 136 K), and magnetic (TN∼ 22 K) phase transitions. The structural transition at TS, resulting in the ordering of the Na ions, and the charge ordering at TC, resulting in the charge redistribution over the positions of V ions, are accompanied by the anomalies in the temperature dependences of all the studied properties. The magnetic ordering at TN results in the appearance of the canted antiferromagnetic structure and manifests itself only in the anomaly in the temperature dependences of the thermal expansion coefficients.