Magnetic and spectroscopic studies of a new ferromagnet BaFeO

Yoshii, Kenji  ; Mizumaki, Masaichiro*; Hayashi, Naoaki*; Matsumura, Daiju   ; Takano, Mikio*

The barium iron oxide BaFeO containing high-valence Fe has been known to have a hexagonal crystal structure. This materials is synthesized under high pressure and shows antiferromagnetic ordering at 160 However, a recent investigation revealed that BaFeO has a cubic structure and shows a ferromagnetic transition at 110 K, if it is prepared in a flow of ozone at a low temperature of 200. In this presentation, we will show magnetic and spectroscopic studies using synchrotron radiation to reveal details of physical properties of this system. Magnetic measurements showed large magnetocaloric effect at around 110 K without hysteretic loss. From magnetic circular dichroism measurements, the small hysteresis is owing to the fact that Fe is actually in the Fe state, which has no orbital magnetic moment. This result suggests that a search for new materials containing Fe is interesting from the viewpoint of development of new magnetic refrigerants.