The AA′3B4O12-type quadruple perovskite LaCu3Ir4O12 prepared at high pressure (9 GPa) and temperature (1523 K) crystallizes in cubic symmetry (Im3, a = 7.52418(3) A˚) with square planar CuO4 and octahedral IrO6 coordination as established from synchrotron powder X-ray diffraction studies. Both crystal structure and X-ray absorption near edge spectroscopy analyses indicate formal oxidation states of LaCu2+3Ir3.75+4O12. The temperature dependence of resistivity of LaCu3Ir4O12 is metallic down to 10 K, with Femiliquid behavior above T∗ ∼ 155 K, and non-Fermi-liquid behavior below T∗. The two-fluid behavior of magnetic susceptibility and the dramatic downturn of the resistivity below T∗ indicate strong Cu2+ 3d and Ir3.75+ 5d orbital hybridization below T∗, also supported by an enhanced electronic specific heat coefficient at low temperature. Theoretical calculations are in good agreement with the experimental results and show that the electronic structure of LaCu3Ir4O12 is different from that of CaCu2+3Ir4+4O12, which is also metallic down to 0.5 K, but presents non-Fermi liquid behavior above T∗ ∼ 80 K and strong Cu-3d-Ir-5d orbital coupling at significantly lower temperature (T < T∗ ∼ 80 K). (Graph Presented).
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry