A Novel Pyrochlore Ruthenate: Ca 2 Ru 2 O 7
نویسنده
چکیده
Single crystals of a novel ruthenate, Ca2Ru2O7, were obtained. An X-ray diffraction study on a single crystal revealed that this material crystallizes in a pyrochlore structure with a lattice parameter, a = 10.197 Å. The magnetic susceptibility above 30 K is the summation of a Curie-Weiss contribution and a constant term independent of temperature. The effective moment per Ru atom is only 0.36 μB, one order of magnitude smaller than that expected from a localized spin model with S = 3/2 for Ru. Below 23 K, the localized spins freeze in a spin-glass state. The resistivity at room temperature is 2 × 10 Ωcm, comparable to that in metallic, highly correlated oxides.
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