Synchrotron X-ray study of filled skutterudites CeFe4Sb12 and Ce0.8Fe3CoSb12

In situ synchrotron X-ray diffraction measurements are carried out on filled skutterudites CeFe4Sb12 and Ce0.8Fe3CoSb12 up to 32 and 20 GPa, respectively, at room temperature. No phase transformation was observed for both samples in the pressure range. Fitting the pressure–volume data (up to 10 GPa) to the third-order Birch–Murnaghan equation of state, the bulk modulus B0 is determined to be 74(4) GPa, with the pressure derivative B′0=7(2) for CeFe4Sb12, and B0=71(2) GPa and B′0=8(2) for Ce0.8Fe3CoSb12. The bulk moduli of filled skutterudites CeFe4Sb12 and Ce0.8Fe3CoSb12 in our study are smaller than those from previous studies on unfilled skutterudite CoSb3. The P–V curves of the unfilled skutterudite CoSb3 and filled skutterudites CeyFe4−xCoxSb12 showed good agreement, indicating that the Ce filling fraction and the replacement of Fe with Co have little effect on their compression behaviors.