EPR STUDY OF LOCAL POSITION FOR FE3+ IN LAYER OXIDE BI2WO6

EPR measurements have been made on a Fe3+ centre in single crystals of Bi2WO6 at room temperature using X-band spectrometer. The fine structure interaction is much stronger than the Zeeman interaction and the principal zeta-axis of the second-rank fine structure tensor is close to the direction of the crystalline layer axis (b-axis). It is found from superposition-model analyses of the fine-structure parameters that the Fe3+ ion substitutes for a Bi3+ ion. The large magnitudes of the parameters b2(0) = 1.40(1), b2(1) = -0.36(1), b2(2) = -0.09(1), b2(-1) = 0.34(1) and b2(-2) = 0.23(1) cm-1 obtained in the (cab)-coordinate system are explained by a deviation of Fe3+ ion mainly along the b-axis, so the piramidal structure of the centre in Bi2O2 layer is flattened from that of host crystal.