Phase transition study in α-Fe2WO6 compound by EPR

The temperature dependence of the EPR spectrum for the alpha-phase of iron tungstate has been investigated in the temperature range of 40-260 K. At temperatures between T-1 approximate to 250 K and T-2 approximate to 205 K where the antiferromagnetic phase transition occurs, a relatively narrow EPR line arising from the dominant iron(III) species has emerged, gaining intensity with the temperature increase. Its linewidth temperature evolution could be described by Huber equation, with T-N = 200 K, which is consistent with the peak seen in magnetic susceptibility measurements, while the corresponding g-factor shifts to higher fields reflecting the build-up of internal field emerging from increasing short-range order in the spin system. At temperatures lower than T-2, a very broad and distorted EPR line with temperature dependent g-factor and linewidth has been observed reflecting the corresponding rise of the magnetic susceptibility below the antiferromagnetic phase transition, presumably arising from magnetic clusters embedded in the antiferromagnetic background.