title: Metallic spin-liquid behavior of the geometrically frustrated Kondo lattice.
abstract: Strongly frustrated magnetism of the metallic pyrochlore oxide Pr2Ir2O7 has been revealed by single crystal study. While Pr 4f moments have an antiferromagnetic RKKY interaction energy scale of /T*/ = 20 K mediated by Ir 5d-conduction electrons, no magnetic long-range order is found except for partial spin freezing at 120 mK. Instead, the Kondo effect, including a lnT dependence in the resistivity, emerges and leads to a partial screening of the moments below /T*/. Our results indicate that the underscreened moments show spin-liquid behavior below a renormalized correlation scale of 1.7 K.
authors.affiliation: Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakatsuji
authors.forename: Y
authors.initials: Y
authors.lastname: Machida
authors.forename: Y
authors.initials: Y
authors.lastname: Maeno
authors.forename: T
authors.initials: T
authors.lastname: Tayama
authors.forename: T
authors.initials: T
authors.lastname: Sakakibara
authors.forename: J van
authors.initials: Jv
authors.lastname: Duijn
authors.forename: L
authors.initials: L
authors.lastname: Balicas
authors.forename: J N
authors.initials: JN
authors.lastname: Millican
authors.forename: R T
authors.initials: RT
authors.lastname: Macaluso
authors.forename: Julia Y
authors.initials: JY
authors.lastname: Chan