High-Pressure Synthesis of Semiconducting PbCu 3 Mn 4 O 12 with Near-Room-Temperature Ferrimagnetic Order.

A transition-metal oxide of PbCu 3 Mn 4 O 12 was prepared at 1523 K and 10 GPa. An A-site-ordered quadruple perovskite structure with the space group Im 3̅ is assigned for this compound. Based on bond-valence-sum calculations and X-ray absorption spectroscopy, the charge combination is determined to be PbCu 3 2+ Mn 4 4+ O 12 . Due to Cu 2+ (↑)-Mn 4+ (↓) antiferromagnetic coupling, a near-room-temperature ferrimagnetic phase transition is observed at approximately 287 K. PbCu 3 Mn 4 O 12 exhibits a semiconducting electric transport property with the energy band gap E g ≈ 0.2 eV. In addition, considerable low-field magnetoresistance effects are observed at lower temperatures. This study provides an intrinsic near-room-temperature ferrimagnetic semiconductor that exhibits potential applications in next-generation spintronic devices.