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Studies of the specific heat and simultaneous AC magnetic susceptibility (χ ) and electric resistance of stoichiometric magnetite single crystal are presented. The temperature hysteresis of the Verwey transition is of 0.03 K found from the specific heat data confirming its first-order character. The continuous temporal change of χ at T V can be switched off by an external magnetic field without affecting the transition. The electrical resistance decreases continuously with increasing temperature with a rapid change of slope at the point when the phase transition is completed. It was concluded that the magnetic degrees of freedom do not actively participate in the transition and that the entropy released at TV may come from ordering electrons.

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Phenomenon related to low symmetry phase of magnetite Fe3O4 below the Verwey transition is the switching of magnetic easy axis by external magnetic field connected with a structural transition. Results of nuclear magnetic resonance (NMR) studies of axis switching are presented, preceded by careful characterization by magnetic measurements. We detect changes in the F57e NMR spectra that evidence the structural transition interrelated with the axis switching. We also observe the switching process in time and analyze the dynamics of the phenomenon. Phenomenological approach according to Kolmogorov–Johnson–Mehl–Avrami is employed to find a link between the experimental data from magnetization measurements and NMR, showing that the effect observed by these two methods has the same origin. Additionally, NMR identifies separately the unswitched and switched phase during the switching process.