NMR of 57Fe above the Verwey transition in Al-substituted magnetite

Electronic structure and hyperfine fields in non-stoichiometric magnetite above the Verwey transition

“…This behavior is clearly connected with the smaller exchange field caused by one missing exchange interaction Fe(A)-O-Fe(B). Similar effect was observed earlier on Al-substituted magnetite [8]. Detailed comparison of these two systems shows that for Fe 3(1Àd) O 4 system the decrease of frequency with increasing temperature is faster, see Fig.…”

NMR of 57Fe, 69Ga and 71Ga in Ga substituted magnetite

“…Our recent [3] and present results of NMR in Al and Ga substituted magnetite support the assumption used [2] for explanation of the stronger effect of Al substitution on the Verwey transition: Al 3+ ions occupy B-sites while Ga 3+ ions prefer A-sites. …”

“…This fact was explained by the assumption that Al 3+ ions occupy Bsites while Ga 3+ ions enter preferentially A-sites. In our previous papers [3,4], we reported the NMR study of Al substituted magnetite.…”

NMR of 57Fe below and around the Verwey transition in Al-substituted magnetite

“…The presence of Al defects in our samples was checked by the A-line spectra satellite structure in the region above the Verwey temperature [2] and by the reduction of T V in agreement with the resistivity measurements in Ref. [1].…”