Anomalous electrical and magnetic properties of a new quasi-low-dimensional mixed-valent molybdenum-cluster compound

• Published in: Materials research bulletin 1993-12, Vol.28 (12), p.1257-1267
• Main Authors: Ramanujachary, K.V., Greenblatt, M., McCarroll, W.H., Goodenough, J.B.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity phenomena in semiconductors and insulators; Electronic transport in condensed matter; Exact sciences and technology; Low-field transport and mobility; piezoresistance; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Physics; Saturation moments and magnetic susceptibilities
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/0025-5408(93)90173-B

Large plate-like single crystals of La 5Mo 4O 16 were prepared by electrolyzing molten mixtures of La 2O 3, MoO 3 and Na 2MoO 4. The temperature dependence of electrical resistivity in the ab plane and parallel to the c-axis of the single crystal shows semiconducting behavior in the temperature range 180–300 K and a sharp upturn in the resistivity below ∼180 K. The temperature variation of the susceptibility in the temperature range 200–300 K follows Curie-Weiss behavior with an observed moment ∼1.66 B.M. corresponding to one localized electron per formula unit. The magnetization study on a batch of randomly oriented single crystals showed a sharp decrease in the susceptibility at ∼180 K indicative of a long-range antiferromagnetic order. Directional magnetization studies on La 5Mo 4O 16 indicated that the magnetic ordering is confined to the ab plane. The anomalous electrical and magnetic properties are discussed in terms of the unique structure of La 5Mo 4O 16.