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arXiv · 1011.0049

Metal-Insulator Transition and Magnetic Order in the Pyrochlore Oxide Hg2Ru2O7

Makoto Yoshida·Masashi Takigawa·Ayako Yamamoto·Hidenori Takagi
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Abstract

We report results of NMR experiments on the ruthenium oxide Hg2Ru2O7 with the pyrochlore structure, which exhibits a metal-insulator transition at TMI = 107 K. In the metallic phase above TMI, the nuclear spin-lattice relaxation rate 1/T1 and the Knight shift at the Hg sites follow the Korringa relation, indicating the absence of substantial spatial spin correlation. At low temperatures in the insulating phase, 99,101Ru-NMR signals are observed at zero magnetic field, providing evidence for a commensurate antiferromagnetic order. The estimated ordered moment is about 1 muB per Ru, much smaller than 3 muB expected for the ionic (4d)3plus configuration of Ru5plus. Thus the localized spin models are not appropriate for the insulating phase of Hg2Ru2O7. We also discuss possible antiferromagnetic spin structures.

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Makoto Yoshida, Masashi Takigawa, Ayako Yamamoto, Hidenori Takagi. 2011-03-31. Metal-Insulator Transition and Magnetic Order in the Pyrochlore Oxide Hg2Ru2O7. https://doi.org/10.1143/jpsj.80.034705

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