Mn2MnReO6: Synthesis and Magnetic Structure Determination of a New Transition-Metal-Only Double Perovskite Canted Antiferromagnet

Transition-metal-only double perovskite oxides (A(2)BB'O-6) are of great interest due to their strong and unusual magnetic interactions; only one compound, Mn2FeReO6, was reported in this category to date. Herein, we report the second transition-metal-only double perovskite, Mn2MnReO6, prepared at high pressure and temperature. Mn2MnReO6 crystallizes in a monoclinic P2(1)/n structure, as established by synchrotron Xray and powder neutron diffraction (PND) methods, with eight-coordinated A sites and rock-salt arrangement of the B and B'-site MnO6 and ReO6. Both the structural analysis and the X-ray absorption near edge spectroscopy results indicate mixed valence states of the B/B'-site in mn(2)(2+)Mn(2+/3+)Re(5+/6+)O(6). The magnetic and PND studies evidence an antiferromagnetic (AFM) transition at similar to 110 K and a transition from a simple AFM to canted AFM with net ferromagnetic component at similar to 50 K. The observed Efros Shklovskii variable-range-hopping semiconducting behavior is attributed to the three (A-site Mn2+, B-site Mn2+/3+, and B'-site Re5+/6+) interpenetrating canted AFM lattices. Theoretical calculations demonstrate that the almost fully polarized Mn states in Mn2MnReO6 are driven away from the Fermi level by static on-site interactions and open a small gap, which is responsible for the insulating state in such a d-electron-rich system. These results provide insight of the electronic origin of the physical properties of Mn2MnReO6 with local electronic structure similar to that of Mn2FeReO6.