Effect of A-site Substitution by Nd~3+ on the Microwave Dielectric Properties of (Pb_0.5Ca_0.5XFe_0.5Nb_0.5)O_3 Ceramics

Microwave dielectric properties of A-site substitution by Nd3+ in(Pb0.5Ca0.5)(Fe0.5 Nb0.5)O3 system were investigated. Microwave dielectric properties of [(Pb0.5Ca0.5)1-xNdx](Fe0.5 Nb0.5)O3 (PCNFN) were improved because the solid solution of small amount of surplus Nd3+ with (Pb,Ca)2+ could eliminate oxygen vacancies. A single perovskite phase was formed when x=0.02. Surplus Nd3+ resulted in the formation of secondary phase (pyrochlore), which can deteriorate to the microwave dielectric properties of PCNFN ceramics. The decreasing of dielectric properties with x content was mainly caused by the formation of pyrochlore. Dielectric constant was above 100 and quality factor Qf values were 5385-5797GHz as x = 0.02 -0.05. Temperature coefficient of resonant frequency (TCF) was changed from positive to negative with the increase of x content.