THE STATES OF COPPER IMPURITIES IN PLZT-8 65/35 RELAXOR - AN ESR STUDY/

ESR investigation of PLZT 8/65/35 relaxer ferroelectric doped by 0.01; 0.1; and 1% of copper oxide was performed at 4.2 K less than or equal to T less than or equal to 300 K in 3 cm and 1.5 cm regions both befo re and after the samples annealing in oxygen and hydrogen atmospheres. The observed spectra were shown to be the superpositions of those Cu2 + in axial and cubic symmetry field. The axial symmetry spectrum is st ipulated by Cu2+ substituted for Ti4+ with its excess charge compensat ion by La3+ in its nearest neighbour, meanwhile cubic symmetry centers are those with the compensation in distant spheres. The sample anneal ing in oxygen atmosphere did not change spectra, meanwhile cubic cente rs completely disappeared on reduced samples and the concentration axi al one decreased. The narrow line which appeared in the reduced sample s near g(elf) = 2.001 was shown to be that the electron trapped by oxy gen vacancy (F-center model). The existance of electric dipoles Cu3+ - La3+ and the dipoles Me3+ -La3+ (Me = Fe, Cr, Mn) in doped by Me ions samples is discussed as the main reason of essential T-c increasing in doped PLZT.