12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone
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Thermal transport in the cage-compounds RFe2Al10 (R=Y, Yb)

Presented by Prof. Andre STRYDOM on 13 Jul 2011 from 17:00 to 19:00
Type: Poster Presentation
Session: Poster1
Track: Track A - Condensed Matter Physics and Material Science


<p>Since the first report of the anomalous magnetic and electronic phenomena in CeRu<sub>2</sub>Al<sub>10</sub> this intermetallic class of compounds, incorporating also members with elements Os and Fe in the place of Ru, have attracted considerable interest. N spite of large interatomic distances antiferromagnetic order sets in at TN =27 K in the ru and Os derivatives, with simultaneous energy gap formation in the electronic energy levels. In this work we studied the electronic and thermal transport in two novel members of the 1:2:10 series, YFe<sub>2</sub>Al<sub>10</sub> and YbFe<sub>2</sub>Al<sub>10</sub>. These two compounds were synthesized with the purpose of studying the effects of a unit cell volume that is compressed well beyond that of CeRu<sub>2</sub>Al<sub>10</sub> in order to expose the role of Fe-based magnetism in the observed electronic correlations. Here we discuss our results of thermal and electronic transport in the pair of compounds YFe<sub>2</sub>Al<sub>10</sub> and YbFe<sub>2</sub>Al<sub>10</sub>. Both exhibit anomalous thermopower behavior and a peak that develops at low temperatures. This is attributed to an enhanced density of states that is achieved through hybridization between conduction electrons and magnetic moments with a localized nature. The thermal conductivity of both compounds shows a weak temperature dependence and especially in the case of YFe<sub>2</sub>Al<sub>10</sub> is the observed behavior amenable to a description in terms of glass-like behavior that most likely results from optical phonon modes which effectively scatter heat-carrying quasiparticles. The electrical resistivity suggests low-lying magnetic cooperative behavior.

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Room: Asteria

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