The effect of La^(3+)and Nd^(3+)on piezoelectric,dielectric and ferroelectric properties of PZT(Pb(Zr_(0.53)Ti_(0.47))O_(3))was studied.The powders were prepared by“wet-chemical”route followed by calcination at 800...The effect of La^(3+)and Nd^(3+)on piezoelectric,dielectric and ferroelectric properties of PZT(Pb(Zr_(0.53)Ti_(0.47))O_(3))was studied.The powders were prepared by“wet-chemical”route followed by calcination at 800℃for 4 h.XRD analysis of the calcined powders confirms the tetragonal phase in the undoped PZT,which gradually decreases with the dopant concentration and the appearance of rhombohedral phase simultaneously.SEM study of sintered pellets reveals the decrease in grain size with the increase in dopant concentration beyond 0.02 mol Nd^(3+)and 0.03 mol La^(3+)respectively.The piezoelectric constant(d_(33))and dielectric properties were maximum for 0.02 mol Nd^(3+)and 0.03 mol La^(3+)respectively.The remnant polarization of La^(3+)-doped sample was higher than Nd^(3+)-doped sample,and the sample with combined dopants shows intermediate remnant polarization(P_(r)).Based on the above study,it is concluded that La^(3+)is more effective than Nd^(3+),including in a mixture of La^(3+)and Nd^(3+)dopants.展开更多
Manganese tetroxide(Mn_(3)O_(4))nanofibers were prepared by electrospinning homogeneous viscous solution of 20 wt%,28 wt%and 36 wt%manganese acetate in poly vinyl alcohol(PVA)and calcining the nanofibers at 1000℃for ...Manganese tetroxide(Mn_(3)O_(4))nanofibers were prepared by electrospinning homogeneous viscous solution of 20 wt%,28 wt%and 36 wt%manganese acetate in poly vinyl alcohol(PVA)and calcining the nanofibers at 1000℃for 2 h.Electrospinning was carried out at 9 kV DC with tip to collector distance(TCD)of 7 cm.Thermo gravimetric analysis(TGA)of the fibers indicates the pure phase of manganese oxide above 500℃.XRD analysis of calcined(at 1000℃)nanofibers indicates the formation of phase-pure tetragonal Mn_(3)O_(4).Scanning electron microscopy(SEM)studies show the fibers cylindrical with the diameters in the range of 100-600 nm and aspect ratio>1000.In general,the average diameter of the green fibers decreases with the increase in manganese acetate concentration.The diameter of calcined nanofibers is reduced by 34%.展开更多
Ba_(0.85)Ca_(0.15)(Ti1−xZrx)O_(3)(BCTZ)ceramics with x=0.05,0.10,_(0.15),0.20,0.25,0.30 were prepared by the solid-state reaction method.Calcination of the powders was carried out at 1100°C for 4 h and the green ...Ba_(0.85)Ca_(0.15)(Ti1−xZrx)O_(3)(BCTZ)ceramics with x=0.05,0.10,_(0.15),0.20,0.25,0.30 were prepared by the solid-state reaction method.Calcination of the powders was carried out at 1100°C for 4 h and the green pellets were sintered at 1400°C for 2 h.X-ray diffraction patterns of the sintered pellets showed tetragonal splitting up to x=0.10 while the mixture of the rhombohedral/cubic phase appeared at higher ZrO_(2)concentrations.Maximum piezoelectric charge constant d33=510 pC/N and strain(S=0.103%)were measured for BCT doped by 0.10 mol ZrO_(2).Dielectric constant,remnant polarization and saturation polarization also found maxima for this composition.The Curie temperature(TC)of the compositions decreased with increase in ZrO_(2)concentration and reached 98°C,87°C and 36°C at x=0.05,0.10,_(0.15)mol,respectively.The remaining compositions have TC below the room temperature;therefore,they can be used for subzero/cryogenic applications.The scanning electron microscopy study revealed an increase in grain size with increase in ZrO_(2)concentration and confirmed the complete solubility of ZrO_(2)in the crystal lattice.Overall,low ZrO_(2)-doped BCT compositions with high d33 could be suitable for low temperature(<80°C)applications.展开更多
文摘The effect of La^(3+)and Nd^(3+)on piezoelectric,dielectric and ferroelectric properties of PZT(Pb(Zr_(0.53)Ti_(0.47))O_(3))was studied.The powders were prepared by“wet-chemical”route followed by calcination at 800℃for 4 h.XRD analysis of the calcined powders confirms the tetragonal phase in the undoped PZT,which gradually decreases with the dopant concentration and the appearance of rhombohedral phase simultaneously.SEM study of sintered pellets reveals the decrease in grain size with the increase in dopant concentration beyond 0.02 mol Nd^(3+)and 0.03 mol La^(3+)respectively.The piezoelectric constant(d_(33))and dielectric properties were maximum for 0.02 mol Nd^(3+)and 0.03 mol La^(3+)respectively.The remnant polarization of La^(3+)-doped sample was higher than Nd^(3+)-doped sample,and the sample with combined dopants shows intermediate remnant polarization(P_(r)).Based on the above study,it is concluded that La^(3+)is more effective than Nd^(3+),including in a mixture of La^(3+)and Nd^(3+)dopants.
文摘Manganese tetroxide(Mn_(3)O_(4))nanofibers were prepared by electrospinning homogeneous viscous solution of 20 wt%,28 wt%and 36 wt%manganese acetate in poly vinyl alcohol(PVA)and calcining the nanofibers at 1000℃for 2 h.Electrospinning was carried out at 9 kV DC with tip to collector distance(TCD)of 7 cm.Thermo gravimetric analysis(TGA)of the fibers indicates the pure phase of manganese oxide above 500℃.XRD analysis of calcined(at 1000℃)nanofibers indicates the formation of phase-pure tetragonal Mn_(3)O_(4).Scanning electron microscopy(SEM)studies show the fibers cylindrical with the diameters in the range of 100-600 nm and aspect ratio>1000.In general,the average diameter of the green fibers decreases with the increase in manganese acetate concentration.The diameter of calcined nanofibers is reduced by 34%.
文摘Ba_(0.85)Ca_(0.15)(Ti1−xZrx)O_(3)(BCTZ)ceramics with x=0.05,0.10,_(0.15),0.20,0.25,0.30 were prepared by the solid-state reaction method.Calcination of the powders was carried out at 1100°C for 4 h and the green pellets were sintered at 1400°C for 2 h.X-ray diffraction patterns of the sintered pellets showed tetragonal splitting up to x=0.10 while the mixture of the rhombohedral/cubic phase appeared at higher ZrO_(2)concentrations.Maximum piezoelectric charge constant d33=510 pC/N and strain(S=0.103%)were measured for BCT doped by 0.10 mol ZrO_(2).Dielectric constant,remnant polarization and saturation polarization also found maxima for this composition.The Curie temperature(TC)of the compositions decreased with increase in ZrO_(2)concentration and reached 98°C,87°C and 36°C at x=0.05,0.10,_(0.15)mol,respectively.The remaining compositions have TC below the room temperature;therefore,they can be used for subzero/cryogenic applications.The scanning electron microscopy study revealed an increase in grain size with increase in ZrO_(2)concentration and confirmed the complete solubility of ZrO_(2)in the crystal lattice.Overall,low ZrO_(2)-doped BCT compositions with high d33 could be suitable for low temperature(<80°C)applications.
