Fig. 1: Characterisation of magnetite samples.
From: Site-selective doping of ordered charge states in magnetite
a Zero-field cooled magnetisations of the powder for sample #1 and the microcrystals #2 and #3, normalised to 140 K values. The fields used were 100 Oe (#1 and #2) and 500 Oe (#3). The Verwey transition for each sample is indicated by a vertical arrow. b Low-temperature splitting of the cubic-(440) powder X-ray diffraction peak for sample #3, demonstrating that a lattice distortion occurs at the Verwey transition between 85 and 90 K. c Thermal evolution of unit-cell parameters derived from fits to powder X-ray profiles for #3 showing the monoclinic splitting at low temperatures. Values for sample #1 at 90 K8, shown as stars, demonstrate that the magnitude of the monoclinic distortion is greatly reduced by doping.
