title: Emergence of a diffusive metal state with no magnetic order near the Mott transition in frustrated pyrochlore-type molybdates.
abstract: The electron-correlation driven metal-insulator (Mott) transition in pyrocholore-type R2Mo2O7(R being rare-earth-metal ions) is accompanied by the change of the magnetic state from ferromagnetic to spin glass due to the competing double-exchange and superexchange interactions on the frustrated lattice. By application of high pressures on the compounds with Mott criticality, however, a new unique paramagnetic metal phase is observed to show up with nearly temperature-independent high resistivity close to the Ioffe-Regel limit. A possible non-Fermi-liquid character of this anomalously diffuse metallic state is argued in terms of the extended double-exchange model with the magnetically frustrated local S=1/2 spins.
authors.affiliation: Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Iguchi
authors.forename: N
authors.initials: N
authors.lastname: Hanasaki
authors.forename: M
authors.initials: M
authors.lastname: Kinuhara
authors.forename: N
authors.initials: N
authors.lastname: Takeshita
authors.forename: C
authors.initials: C
authors.lastname: Terakura
authors.forename: Y
authors.initials: Y
authors.lastname: Taguchi
authors.forename: H
authors.initials: H
authors.lastname: Takagi
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura