Resistance Anomaly in Quasi-One-Dimensional Sulfide BaNbS_3+δ

Author： Kijima N. Morie K. Chikazawa S. Nishihara H. Nagata S.

ISSN： 0022-4596

Source： Journal of Solid State Chemistry, Vol.142, Iss.1, 1999-01, pp. : 57-62

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Abstract

Single-phase specimens of hexagonal BaNbS_3+δ (2.93≤3+δ≤3.06) have been successfully prepared by the sulfurization method using CS₂. The lattice constants, a and c, are less sensitive to the value of δ in the region of -0.07≤δ≤0.06. BaNbS_2.93 indicates a semiconductor-to-semiconductor gradual transition around 100 K. On the other hand, BaNbS_3+δ (2.96≤3+δ≤3.06) shows hump-shaped anomalous behaviors in the resistivity. Although the anomalies in the electrical resistivity have been observed, all the samples have indicated no anomaly in their magnetic susceptibility. The magnetic susceptibilities are nearly temperature independent with extremely small Curie-like behavior at low temperatures. BaNbS_2.98 does not undergo a structural phase transition and there is no change in symmetry down to 80 K, above which the hump-shaped anomaly is clearly found. The relationship in the resistance anomaly between BaNbS_3+δ and BaVS₃ seems to be significant and to have an important role in clarifying the mechanism of these anomalies.