Elemental substitution effects in multiferroic FeO (: rare earths)

Yoshii, Kenji  ; Funae, Takeshi*; Mizumaki, Masaichiro*; Ejiri, Hiroki*; Ikeda, Naoshi*; Saito, Hiroyuki; Matsumura, Daiju   

We report the effects of elemental substitutions in multiferroic FeO (: Y, Ho-Lu, In). The substitution by nonmagnetic Ga at the Fe site, which has not been reported so far, shows a drastic decrease in the ferrimagnetic transition temperature (). This is plausibly owing to the suppression of magnetic interactions between Fe ions, based on our previous results of other substituted systems such as FeCoO. Dielectric constants near room temperature were comparable to those of FeO. The suppression of dielectric loss in this system is suitable to application. The -site substitution was also attempted by the large R ions such as Dy. The solubility limit was up to about 10% of ions, as confirmed by XRD and EXAFS measurements. was raised by 5-10 K for Dy substitution.