Observation of A-site antiferromagnetic and B-site ferrimagnetic orderings in the quadruple perovskite oxide CaCu3Co2Re2O12

A quadruple perovskite oxide CaCu3Co2Re2O12 was synthesized by high-pressure annealing. This compound crystallizes in an A- and B-site ordered quadruple perovskite structure with space group Pn-3. The charge combination is determined to be CaCu2+ Co-3(2+) Re-2(6+) O-2(12) by bond valence sum analysis and x-ray absorption spectroscopy. In contrast to other isostructural ACu(3)B(2)B(2)'O-12 compounds with a single magnetic transition, a long-range antiferromagnetic phase transition originating from the A'-site Cu2+ sublattice is found to occur at T-N approximate to 28K. Subsequently, the spin coupling between the B-site Co2+ and B'-site Re6+ ions contributes to a ferrimagnetic transition around T-C approximate to 20K. Strong electrical insulating behavior is identified by optical measurement with an energy gap of approximately 3.75 eV. The mechanisms of the spin interactions are discussed in detail.

Automated summary

A quadruple perovskite oxide CaCu3Co2Re2O12 was synthesized by high-pressure annealing, showing unique A- and B-site ordered quadruple perovskite structure. It exhibits long-range antiferromagnetic and ferrimagnetic phase transitions, with strong electrical insulating behavior and an energy gap of approximately 3.75 eV. Spin interactions mechanisms are discussed in detail.