NMR in magnetite below and around the Verwey transition

NMR on Fe-57 nuclei was measured in two single crystals of magnetite betwee n 4.2 and 135 K (temperature of the Verwey transition T-V = 121.5 and 123.9 K). We were able to register all lines detected at 4.2 K also at higher te mperatures up to T-V. The spectra are compatible with the space group Cc, w hich predicts 8 and 16 lines for iron on tetrahedral (A) and octahedral (B) sites, respectively. One of the Fe(A) lines is doubly degenerate for all T e TV, which restricts the possible models of the Fe2+ and Fe3+ ordering on the B sites. Above T-V no remnant of the low-temperature spectrum was detec ted. At 4.2 K the NMR spin-spin and spin-lattice relaxation times were dete rmined.