PHASE-TRANSITION STUDY IN ALPHA-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 40-26 0 K. At temperatures between T-1 approximate to 250 K and T-2 approxim ate to 205 K where the antiferromagnetic phase transition occurs, a re latively narrow EPR line arising from the dominant iron(III) species h as emerged, gaining intensity with the temperature increase. Its linew idth temperature evolution could be described by Huber equation, with T-N = 200 K, which is consistent with the peak seen in magnetic suscep tibility measurements, while the corresponding g-factor shifts to high er fields reflecting the build-up of internal field emerging from incr easing short-range order in the spin system. At temperatures lower tha n 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.