Enhancement of A′-site Mn3+ spin ordering by B-site Mn4+ substitution in quadruple perovskite PbMn3Cr3MnO12

An A-site ordered but B-site disordered quadruple perovskite oxide PbMn3Cr3MnO12 was synthesized by high-pressure and high-temperature methods. The compound crystallizes in space group Im-3 with the charge distribution of Pb2+Mn33+Cr33+Mn4+O12. Three antiferromagnetic phase transitions are found to occur at T-N1 approximate to 155, T-N2 approximate to 81, and T-N3 approximate to 74K, respectively, due to the complex B-site and A ' -B intersite spin interactions. Compared with the isostructural LaMn3Cr4O12 with negligible A ' -B intersite spin coupling, the substitution of Mn4+, which has identical electronic configuration to that of Cr3+ (t(2g)(3)), into the B site can introduce A ' -B intersite spin interactions. As a result, the A ' -site spin-related ordering temperature increases significantly, while the B-site one remains little changed in the current PbMn3Cr3MnO12. This work opens up a way to enhance the A ' -site spin ordering temperature in quadruple perovskite oxides.

Automated summary

The A-site ordered but B-site disordered quadruple perovskite oxide PbMn3Cr3MnO12 was synthesized using high-pressure and high-temperature methods. The compound shows three antiferromagnetic phase transitions at approximately 155K, 81K, and 74K, respectively, due to complex spin interactions. Introducing Mn4+ ions into the B site increases the A-site spin-related ordering temperature significantly.