T Labii, M Ceretti, A Boubertakh, W Paulus, S Hamamda


The numerous studies conducted on the structure of CaFeO2.5 showed that the material undergoes a series of transformations based on temperature. The first one appears around 700 K and indicates the evolution of the phasemagnetic material to a paramagnetic phase. At about 970 K the structure of CaFeO2.5 changes from rhombohedral to centered structure. Finally, around 1180 K it undergoes the transition to a structure that has been described as incommensurate modulated structure. We have observed the behavior of the material beyond this temperature by dilatometry, DSC and TGA. The tests conducted on a single crystal CaFeO2.5 confirm the changes already observed.For the first time there was a dilatometric anomaly (confirmed by DSC and TGA) at 1310 K. This anomaly appears only in the crystallographic direction b which should probably be a  commensurate transformation of the material.


Dilatometry; DSC; TGA; Dilatométrie

Texte intégral :



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