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

被引：10

作者：

Yoshida, Makoto ^{[1
]}

Takigaway, Masashi ^{[1
]}

Yamamoto, Ayako ^{[2
]}

Takagi, Hidenori ^{[2
,3
]}

机构：

[1] Univ Tokyo, Inst Solid State Phys, Chiba 2778581, Japan

[2] RIKEN Adv Sci Inst, Wako, Saitama 3510198, Japan

[3] Univ Tokyo, Dept Adv Mat, Chiba 2778561, Japan

来源：

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN | 2011年 / 80卷 / 03期

基金：

日本学术振兴会;

关键词：

pyrochlore structure; ruthenium oxide; Hg2Ru2O7; NMR; metal-insulator transition; magnetic order; GEOMETRICALLY FRUSTRATED ANTIFERROMAGNET; QUANTUM SPIN LIQUID; LATTICE; RELAXATION; DISORDER; LIV2O4;

D O I：

10.1143/JPSJ.80.034705

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We report results of NMR experiments on the ruthenium oxide Hg2Ru2O7 with the pyrochlore structure, which exhibits a metal-insulator transition at T-MI = 107 K. In the metallic phase above TMI, the nuclear spin-lattice relaxation rate 1/T-1 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, Ru-99,Ru-101-NMR signals are observed at zero magnetic field, providing evidence for a commensurate antiferromagnetic order. The estimated ordered moment is about 1 mu(B) per Ru, much smaller than 3 mu(B) expected for the ionic (4d)(3) configuration of Ru5+. Thus, the localized spin models are not appropriate for the insulating phase of Hg2Ru2O7. We also discuss possible antiferromagnetic spin structures.

引用

页数：9

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