%A Youwen Long(龙有文) %T A-site ordered quadruple perovskite oxides AA3'B4O12 %0 Journal Article %D 2016 %J Chin. Phys. B %R 10.1088/1674-1056/25/7/078108 %P 78108-078108 %V 25 %N 7 %U {https://cpb.iphy.ac.cn/CN/abstract/article_118773.shtml} %8 2016-07-05 %X

The A-site ordered perovskite oxides with chemical formula AA3'B4O12 display many intriguing physical properties due to the introduction of transition metals at both A' and B sites. Here, research on the recently discovered intermetallic charge transfer occurring between A'-site Cu and B-site Fe ions in LaCu3Fe4O12 and its analogues is reviewed, along with work on the magnetoelectric multiferroicity observed in LaMn3Cr4O12 with cubic perovskite structure. The Cu-Fe intermetallic charge transfer (LaCuLaCu33+Fe43+O12→LaCu32+Fe43.75+O12) leads to a first-order isostructural phase transition accompanied by drastic variations in magnetism and electrical transport properties. The LaMn3Cr4O12 is a novel spindriven multiferroic system with strong magnetoelectric coupling effects. The compound is the first example of cubic perovskite multiferroics to be found. It opens up a new arena for studying unexpected multiferroic mechanisms.