High-Pressure Synthesized Perovskite CdMnO 3 with C-Type Antiferromagnetic Spin Configuration.

CdMnO 3 had not been previously reported and was a missing piece in the A 2+ Mn 4+ O 3 series. We succeeded in synthesizing this compound by a high-pressure method and confirmed that it is crystallized in a distorted perovskite structure with a Cd 2+ Mn 4+ O 3 charge configuration. The obtained insulating CdMnO 3 exhibits an antiferromagnetic transition at about 86 K. First-principles calculations revealed that the Mn 4+ ( t 2g 3 ) spins form a C-type antiferromagnetic structure, which is in sharp contrast to the G-type antiferromagnetism in the isostructural and isoelectronic CaMnO 3 . Significant overlap of the Mn-3d and O(2)-2p orbitals produces distorted octahedra with a large Mn-O(1)-Mn tilt and induces antiferromagnetic couplings in the ac plane and the ferromagnetic couplings along the b axis.