(1-x)Pb(Fe

1/2

Nb

1/2

)O

3

-xPbTiO

3

(PFN-PT) ferroelectric ceramics were prepared by the conventional ceramic processing via the wolframite precursor method. The X-ray diffraction (XRD) measurement and density measurement confirmed that the PFN-PT ceramics sintered at 1 150 ℃ for 2.5 h exhibited pure perovskite structure and high relative density. With the increase of the content of PbTiO

3

(PT)

the crystal structure of PFN-PT changed gradually from the rhombohedral perovskite structure to the tetragonal perovskite structure

while the cell volume decreased and the tetragonality (defined as the ratio of the cell parameters c/a) of the perovskite structure increased. The PFNPT ceramics exhibited apparent dielectric frequency dispersion. With the increase of the PT content

the temperature of dielectric maximum T

m

/T

C

increased

the dielectric response character changed from diffused and broad dielectric peaks to relatively sharper ones

the dielectric loss decreased

and the frequency dispersion became weak. The doping of MnO

2

improved dielectric property of the PFN-PT ceramics effectively

in which the values of dielectric constant maximum ε

m

and roomtemperature dielectric loss tan δ were 13 254 and 0.003 63

respectively

at 100 kHz

and the values of saturation polarizationP

s

coercive fieldE

c

and piezoelectric constant d

33

 were 6.18 μC/cm

2

1.1 kV/mm and 98pC/N

respectively

of the 0.25% MnO

2

doped 0.66PFN-0.34PT ceramics.