J. Phys. Soc. Jpn. 70 (2001) pp. 2880-2883  |Next Article|  |Table of Contents|
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Metal-Nonmetal Changeover in Pyrochlore Iridates

Daiki Yanagishima^1, and Yoshiteru Maeno^1,2,3,

(Received June 19, 2001)

We report the low temperature properties of a new series of pyrochlore iridates R₂Ir₂O₇ (R=rare-earth elements). We found that the compounds with R=Pr, Nd, Sm, and Eu exhibit metallic conductivity, whereas those with smaller rare-earth ions are nonmetallic. Such metal-nonmetal changeover is attributable to the importance of electron correlation among the Ir 5d electrons. Reflecting the geometrical frustration in the pyrochlore lattice, the rare-earth moments do not exhibit magnetic ordering to temperatures well below the antiferromagnetic Weiss temperature. We did not find any sign of superconductivity down to 0.3 K in these compounds. ©2001 The Physical Society of Japan

KEYWORDS: pyrochlore, R₂Ir₂O₇, geometrical frustration, iridates, specific heat
URL: http://jpsj.ipap.jp/link?JPSJ/70/2880/
DOI: 10.1143/JPSJ.70.2880

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