Observation of A -site antiferromagnetic and B -site ferrimagnetic orderings in the quadruple perovskite oxide CaCu$_{3}$Co$_{2}$Re$_{2}$O$_{12}$

A quadruple perovskite oxide CCaCu$_{3}$Co$_{2}$Re$_{2}$O$_{12}$ 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 CaCu$^{2+}_3$Co$^{2+}_2$Re$^{6+}_2$O$_{12}$ 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 Cu$^{2+}$ sublattice is found to occur at T$_N ≈$ 28K. Subsequently, the spin coupling between the B-site Co$^{2+}$ and B′-site Re$^{6+}$ ions contributes to a ferrimagnetic transition around T$_C ≈$ 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