Magnetic and thermoelectric properties of BayFe4-xCoxSb12

• Published in: Physica. B, Condensed matter Condensed matter, 2006-08, Vol.383 (1), p.132-133
• Main Authors: MATSUOKA, E, MORIMOTO, S, TANAKA, K, SASAKAWA, T, TAKABATAKE, T
• 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; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Physics; Saturation moments and magnetic susceptibilities; Thermoelectric and thermomagnetic effects
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2006.03.078

We report the measurements of magnetic and thermoelectric properties of BayFe4-xCoxSb12 (x=0, 1, 2, 2.5, 3). The host compound BaFe4Sb12 is a nearly ferromagnetic metal. With increasing x to 2.5, the resistivity increases by one order of magnitude and both the magnetic susceptibility and electronic specific heat coefficient decrease. A diamagnetic behavior for x=2.5 indicates that the Co substitution leads to a strong decrease of the electronic density of states near the Fermi level. The thermopower for x=0 exhibits local maximum at 50K, which disappears for x1. A positive thermopower of 135muV/K at 500K for x=2.5 changes to a negative one, -120muV/K for x=3.0. This reversal of the sign indicates that the electron carries doped with the Co substitution overcompensates for the hole carriers in this system.