MAGNETIC PROPERTY OF OXIDE WITH THE PEROVSKITE STRUCTURE, A(2)FE(III)BO6 (A=CA, SR, BA AND B=SB, BI)

In the course of magnetic study on several perovskite-type oxides, A(2 )Fe(III)BO6 (A=Ca, Sr, Ba, and B=Sb, Bi), we have observed a strong ir reversibility in their dc-magnetizations. When the structural data and the Mossbauer spectra are considered, such an irreversibility is to b e associated with some competitions between the nearest-neighbors (nn) and the next-nearest-neighbors (nnn) in their magnetic sublattices. P articularly, the Mossbauer spectra indicate that Sr2FeBiO6 of cubic pe rovskite-structure is apparently well ordered crystalline compound. No ntheless this antiferromagnet shows a magnetic property which resemble s that of a spin-glass. The strong history dependence is observed belo w 91 K and the irreversible magnetic behavior is also observed from th e measurement of hysteresis loops at 10 K after zero-field-cooled (zfc ) and field-cooled (fc) processes. Considering the nn and the nnn supe rexchanges of almost same order in ordered perovskite, it is proposed that there exists a competition and cancellation of antiferromagnetic and ferromagnetic superexchange between the nearest-neighbors and the next-nearest-neighbors, thus introducing a certain degree of frustrati on.