ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 40, Number 9
JKCSEZ 40(9)
June 20, 1996 

The structural changes and dielectric properties of Pb_1-x(Na_1/2La_1/2)_x(Mg_1/3Nb_2/3)O₃ compounds substituted by 0∼50 mol.% of Na+/La3+ mixed ions were investigated by X-ray diffraction method, IR and Raman spectroscopy, and LCR meter. The amount of perovskite phase increased with the increases of Na+/La3+ substituents and sintering temperatures. Although the superlattice lines due to 1:1 ordering were not detected by X-ray diffraction method, it was found, from the Raman spectroscopy and the increase of diffuseness coefficient, that the ordering behavior was related to the decrease of A site ion size. Dielectric properties in Pb_1-x(Na_1/2La_1/2)_x(Mg_1/3Nb_2/3)O₃ were affected by the amount of perovskite phase, grain size, and density. The phase transitions were broadened and phase transition temperatures were lowered by the increase of Na+/La3+ ions.