Solana-Madruga Elena, Kearins Padraig S, Ritter Clemens, Arévalo-López Ángel M, Attfield J Paul
Centre for Science at Extreme Conditions (CSEC) and School of Chemistry, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3JZ, UK.
Departamento de Química Inorgánica, Facultad CC. Químicas, Universidad Complutense de Madrid, Spain.
Angew Chem Int Ed Engl. 2022 Oct 4;61(40):e202209497. doi: 10.1002/anie.202209497. Epub 2022 Aug 26.
Cation ordering in ABX perovskites is important to structural, physical and chemical properties. Here we report discovery of CaCuFeReO with the tetragonal AA'BB'O double double perovskite structure that was previously only reported for A'=Mn compositions. CaCuFeReO occurs in the same phase field as CaCu Fe Re O demonstrating that different A-cation ordered peroskites may be obtained in the same chemical system. CaCuFeReO has ferrimagnetic order of Fe, Re and Cu spins below T =567 K, in contrast to Mn analogues where the Mn spins order separately at much lower temperatures. The magnetoresistance of CaCuFeReO displays low-field "butterfly" hysteresis with an unusual change from negative to positive values as field increases. Many more AA'BB'O double double perovskites may be accessible for A'=Cu and other divalent transition metals at high pressure, so the presently known phases likely represent only the "tip of the iceberg" for this family.
ABX钙钛矿中的阳离子有序化对其结构、物理和化学性质至关重要。在此，我们报告发现了具有四方AA'BB'O双钙钛矿结构的CaCuFeReO，该结构此前仅在A' = Mn成分中被报道过。CaCuFeReO与CaCuFeReO处于同一相区，这表明在同一化学体系中可能获得不同的A阳离子有序钙钛矿。CaCuFeReO在T = 567 K以下具有Fe、Re和Cu自旋的亚铁磁有序，这与Mn类似物不同，在Mn类似物中，Mn自旋在低得多的温度下分别有序。CaCuFeReO的磁电阻显示出低场“蝴蝶”磁滞现象，随着磁场增加，其值会出现从负值到正值的异常变化。对于A' = Cu和其他二价过渡金属，在高压下可能会有更多的AA'BB'O双钙钛矿出现，因此目前已知的相可能仅代表该家族的“冰山一角”。
