THE RARE-EARTH DEPENDENCE ON THE SOLID-SOLUTION FORMATION AND ELECTRICAL-PROPERTIES OF KCA2-XRXNB3O10 (R=ND, SM, GD AND CE)

The solid solution KCa2-xRxNb3O10 (R = Nd, Sm, Gd and Ce) was prepared by solid-state reaction using KCa2Nb3O10, KNbO3, Nb2O5, Nb and rare-e arth oxides, The solubility limit of the solid solutions was extended with an increase in the ionic radii of the rare earths. All the solid solutions exhibited similar semiconductive behavior with a linear log p-T relationship over a wide temperature range. These results suggest that the conduction mechanism is independent of the type of rare earth s and also the unit-cell parameters, which. agrees well with the tunne ling conduction model with a vibrating barrier.