Metallic Behavior in A-Site-Ordered Perovskites ACu3V4O12 with A = Na+, Ca2+, and Y3+

The A -site-ordered perovskites A Cu 3 V 4 O 12 ( A = Na + , Ca 2+ , and Y 3+ ) have been found to be Pauli paramagnetic metals. Bond valence sum calculations, magnetic susceptibility measurement, and electronic structure calculations reveal that both Cu and V orbitals contribute to the metallic conduction. Changing the A -site ions in A Cu 3 V 4 O 12 from monovalent to divalent to trivalent ions changes the physical properties in ways that in a rigid band picture can be attributed to the shift of the Fermi energy. The A Cu 3 V 4 O 12 compounds, unlike the isostructural metallic CaCu 3 Ru 4 O 12 , show no conclusive evidence of heavy-fermion-like behavior.