title: Nature of the transition between a ferromagnetic metal and a spin-glass insulator in pyrochlore molybdates.
abstract: The metal-insulator transition has been investigated for pyrochlore molybdates R(2)Mo(2)O(7) with nonmagnetic rare-earth ions R. The dynamical scaling analysis of ac susceptibility reveals that the geometrical frustration causes the atomic spin-glass state. The reentrant spin-glass phase exists below the ferromagnetic transition. The electronic specific heat is enhanced as compared to the band calculation result, perhaps due to the orbital fluctuation in the half-metallic ferromagnetic state. The large specific heat is rather reduced upon the transition, likely because the short-range antiferromagnetic fluctuation shrinks the Fermi surface.
authors.affiliation: Department of Applied Physics, University of Tokyo, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hanasaki
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Ohtsuka
authors.forename: I
authors.initials: I
authors.lastname: Kézsmárki
authors.forename: S
authors.initials: S
authors.lastname: Iguchi
authors.forename: S
authors.initials: S
authors.lastname: Miyasaka
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura
mesh_terms: D005898:Glass; D059346:Magnets; D008670:Metals; D008956:Models, Chemical; D044366:Transition Temperature
chemical_list: D008670:Metals