Polycrystalline(Bi_(0.94)Na_(0.94))_(0.5)Ba_(0.06)TiO_(3)ceramics(r=0,0.04,and 0.08,designated as BNBT6:BNBT6:4Dy and BNBT6.8Dy,respectively)were prepared by conventional high tem-perat ure sintering method.The X-ray ...Polycrystalline(Bi_(0.94)Na_(0.94))_(0.5)Ba_(0.06)TiO_(3)ceramics(r=0,0.04,and 0.08,designated as BNBT6:BNBT6:4Dy and BNBT6.8Dy,respectively)were prepared by conventional high tem-perat ure sintering method.The X-ray difraction patterms show pure perovskite structure with no secondary phases.Lattice parameters and unit cell volumes have decreased due to Dy_(2)O_(3)substi-tution.SEM micrographs revealed denser samples(prel>97%)with wmiformly distributed grainsizes.The room temperature piezoelectric properties of Dy_(2)O_(3)substit ut ed sample at a=0.04 wererelatively higher.d_(33)=147 pC/N,k_(p)=28%and Q_(m)=-128.The samples exhibited infinitesimalchange in thickness(α15 nm)to an applied voltage of 100 V,which could be utilized in actuatorapplications.Relaxor behavior and broad dielectric maxima with diffuse phase transition wereobser ved.The value of RT dielectric constant has increased while dielectric loss was decreased dueto Dy_(2)O_(3),substitution.Conductivity in the materials obeys Jonscher's universal power law.The conductivity in the low frequency region is associated with short range translational hopping whileit is associated with the reorientational hopping in the high frequency region.The charge carrier concentration term remained constant over the entire temperature range of(30-500°C).展开更多
文摘Polycrystalline(Bi_(0.94)Na_(0.94))_(0.5)Ba_(0.06)TiO_(3)ceramics(r=0,0.04,and 0.08,designated as BNBT6:BNBT6:4Dy and BNBT6.8Dy,respectively)were prepared by conventional high tem-perat ure sintering method.The X-ray difraction patterms show pure perovskite structure with no secondary phases.Lattice parameters and unit cell volumes have decreased due to Dy_(2)O_(3)substi-tution.SEM micrographs revealed denser samples(prel>97%)with wmiformly distributed grainsizes.The room temperature piezoelectric properties of Dy_(2)O_(3)substit ut ed sample at a=0.04 wererelatively higher.d_(33)=147 pC/N,k_(p)=28%and Q_(m)=-128.The samples exhibited infinitesimalchange in thickness(α15 nm)to an applied voltage of 100 V,which could be utilized in actuatorapplications.Relaxor behavior and broad dielectric maxima with diffuse phase transition wereobser ved.The value of RT dielectric constant has increased while dielectric loss was decreased dueto Dy_(2)O_(3),substitution.Conductivity in the materials obeys Jonscher's universal power law.The conductivity in the low frequency region is associated with short range translational hopping whileit is associated with the reorientational hopping in the high frequency region.The charge carrier concentration term remained constant over the entire temperature range of(30-500°C).
