Mössbauer effect study of Bi2Fe4O9

The electronic properties of complex oxides of bismuth with the mullite structure

“…The general features of this spectrum, for which the Mössbauer parameters are shown in Table 2, are consistent with previously-reported spectra. 16,23 SEM images of the sintered pellet prior to the electronic measurements (Fig. 4B) showed a homogeneous sample with no evidence of a glassy phase.…”

“…A more detailed mechanism has been proposed for oxide ion conductance in this compound, invoking the polarizability of the Bi 6 s 2 lone pairs of electrons. 14 Although the magnetic properties of the ferrate have been more extensively investigated, [15][16][17][18][19][20][21][22][23] suggesting the occurrence of a paramagnetic-to-antiferomagnetic transition at a Neel temperature of −9 • C the electronic properties of this and the other isostructural compounds have not been investigated systematically. The present study aims to remedy this deficiency by investigating the electronic behaviour of a series of wellcharacterized sintered polycrystalline samples as a function of temperature and frequency.…”

The magnetic structure of Bi2Fe4O9– analysis of neutron diffraction measurements

“…A transition from para-to antiferromagnetism at Ts = 265 K was found in the magnetic susceptibility (Tutov et al, 1964) and MSssbauer effect (Bokov, Novikov, Trukhtanov & Yushchuk, 1970;Kostiner & Shoemaker, 1971;Bokov, Yushchuki, Popov, Parfenova & Tutov, 1971;Bokov, Kamzin & Karapet'yan, 1973) studies of this compound. A transition to a k ~ 0 magnetic structure was predicted by Bokov et al (1971).…”

Compositional dependence of hyperfine interactions and magnetoelectric coupling in (BiFeO3)x-(BaTiO3)1–x solid solutions

“…5a). In the case of x = 0.9 the doublets are attributed to the paramagnetic [16]. For samples where x = 0.8 and 0.7, the doublets with parameters  = 0.35-0.37 mm/s and  = 0.51-0.52 mm/s may be related to the regular phase present in these samples.…”