Emergence of a diffusive metal state with no magnetic order near the Mott transition in frustrated pyrochlore-type molybdates.
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.
Iguchi
S
S
Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
Hanasaki
N
N
Kinuhara
M
M
Takeshita
N
N
Terakura
C
C
Taguchi
Y
Y
Takagi
H
H
Tokura
Y
Y