A -site quadruple perovskite manganites AMn7O12 ( A=Sr , Cd, and Pb)

 Powder samples of SrMn7O12, CdMn7O12, and PbMn7O12 were prepared from stoichiometric mixtures of Mn2O3, MnO1.839 (Alpha Aesar MnO2 99.997% with the precise oxygen content determined by thermogravimetric analysis), PbO (99.999%), CdO (99.99%), and 4H-SrMnO3. The mixtures were placed in Au capsules and treated at 6 GPa and 1373 K for 2 h for CdMn7O12 and PbMn7O12 and at 6 GPa and 1573 K for 2 h for SrMn7O12 (the duration of heating to the desired temperatures was 10 min) in a belt-type high-pressure apparatus. After the heat treatments, the samples were quenched to room temperature, and the pressure was slowly released.
MnO2
99.997%
%
PbO
99.999%
%
CdO
99.99%
%
CdMn7O12 and PbMn7O12
treated
6 GPa
GPa
CdMn7O12 and PbMn7O12
treated
1373 K
K
CdMn7O12 and PbMn7O12
treated
2 h
h
SrMn7O12
treated
6 GPa
GPa
SrMn7O12
treated
1573 K
K
SrMn7O12
treated
2 h
h
mixtures were placed in Au capsules
duration of heating to the desired temperatures
10 min
min