Charge and orbital orders and structural instability in high-pressure quadruple perovskite CeCuMn 6 O 12
2018
We prepared a quadruple perovskite CeCuMn6O12 under high-pressure and high-temperature conditions at 6 GPa and about 1670 K and investigated its structural, magnetic and transport properties. CeCuMn6O12 crystallizes in space group Im-3 above T CO = 297 K; below this temperature, it adopts space group R-3 with the 1:3 (Mn4+:Mn3+) charge and orbital orders. Unusual compressed Mn3+O6 octahedra are realized in CeCuMn6O12 similar to CaMn7O12 with the -Q 3 Jahn-Teller distortion mode. Below about 90 K, structural instability takes place with phase separation and the appearance of competing phases; and below 70 K, two R-3 phases coexist. CeCuMn6O12 exhibits a ferromagnetic-like transition below T C = 140 K, and it is a semiconductor with the magnetoresistance reaching about -40% at 140 K and 70 kOe. We argued that the valence of Ce is +3 in CeCuMn6O12 with the Ce3+([Formula: see text])([Formula: see text])O12 charge distribution in the charge-ordered R-3 phase and Ce3+([Formula: see text])([Formula: see text])O12 in the charge-disordered Im-3 phase.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
35
References
4
Citations
NaN
KQI