Lead-free Bi_(_(0.5))Na_(_(0.5))TiO_(3)(BNT)piezoelectric ceramics have the advantages of large coercive fields and high Curie temperatures.But the improvement of piezoelectric coefficient(d 33)is usually accompanied ...Lead-free Bi_(_(0.5))Na_(_(0.5))TiO_(3)(BNT)piezoelectric ceramics have the advantages of large coercive fields and high Curie temperatures.But the improvement of piezoelectric coefficient(d 33)is usually accompanied by a huge sacrifice of depolarization temperature(T d).In this work,a well-balanced performance of d 33 and T d is achieved in MnO_(2)-doped 0.79(Bi_(_(0.5))Na_(_(0.5))TiO_(3))-0.14(Bi_(0.5)K_(0.5)TiO_(3))-0.07BaTiO_(3)ternary ceramics.The in-corporation of 0.25 mol%MnO_(2)enhances the d 33 by more than 40%,while T d remains almost unchanged(i.e.,d 33=181 pC/N,T d=184℃).X-ray diffraction(XRD)shows that an appropriate fraction of the small axis-ratio ferroelectric phase(pseudo-cubic,P c)coexists with the long-range ferroelectric phase(tetrag-onal,T)under this MnO_(2)doping.Piezoelectric force microscopy(PFM)has revealed a special domain configuration,namely large striped and layered macro domains embedded with small nanodomains.This study provides a distinctive avenue to design BNT-based piezoelectric ceramics with high piezoelectric performance and temperature stability.展开更多
The influence of temperature on mode coupling effect in piezoelectric vibrators remains unclear.In this work,we discuss the influence of temperature on two-dimensional(2D)mode coupling effect and electromechanical cou...The influence of temperature on mode coupling effect in piezoelectric vibrators remains unclear.In this work,we discuss the influence of temperature on two-dimensional(2D)mode coupling effect and electromechanical coupling coefficient of cylindrical[001]c-poled Mn-doped 0.24PIN-0.46PMN-0.30PT piezoelectric single-crystal vibrator with an arbitrary configuration ratio.The electromechanical coupling coefficient kt decreases with temperature increasing,whereas k33 is largely invariant in a temperature range of 25℃-55℃.With the increase of temperature,the shift in the‘mode dividing point’increases the scale of the poling direction of the piezoelectric vibrator.The temperature has little effect on coupling constantΓ.At a given temperature,the coupling constantΓof the cylindrical vibrator is slightly greater than that of the rectangular vibrator.When the temperature changes,the applicability index(M)values of the two piezoelectric vibrators are close to 1,indicating that the coupling theory can be applied to piezoelectric vibrators made of late-model piezoelectric single crystals.展开更多
Er^(3+)-modified 0.68 Pb(Mg_(1/3)Nb_(2/3))O_3-0.32 PbTiO_3(PMN-32 PT) single crystals were grown by using the flux method. The growth mechanism of the crystal and influences of Er^(3+) ions on phase structure,electric...Er^(3+)-modified 0.68 Pb(Mg_(1/3)Nb_(2/3))O_3-0.32 PbTiO_3(PMN-32 PT) single crystals were grown by using the flux method. The growth mechanism of the crystal and influences of Er^(3+) ions on phase structure,electrical and optical properties were investigated. Results reveal that the crystals are still pure perovskite structure with Er3+ ions doping, but lattice enlarges slightly. The coercive electric field is increased from 4.83 to 6.37 kV/cm for [100]-oriented crystals comparing to undoped PMN-32 PT single crystals.Moreover, the crystal exhibits upconversion emission properties. Green(531 and 552 nm) and red(670 nm) emission bands are recorded under the excitation of 980 nm diode laser, which correspond to the ~2 H_(11/2)→~4 I_(15/2), ~4 S_(3/2)→~4 I_(15/2) and ~4 F_(9/2)→~4 I_(15/2) transitions of Er^(3+) ions. Our results show the feasibility of using this crystal in photoelectric multifunctional devices.展开更多
The [001]c-polarized(1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN-PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field( 2 kV/cm) of...The [001]c-polarized(1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN-PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field( 2 kV/cm) of such crystals restricts their application at high frequencies because the driving field will exceed the coercive field. The depolarization field can be considerably larger in an antiparallel direction than in a parallel direction with respect to polarization when the bipolar driving cycle starts. Thus, if the direction of the sine wave signal in the first half cycle is opposite to the polarization direction, then the depolarized domains can be repolarized in the second half of the sine cycle. However, if the direction of the sine wave signal in the first half of the cycle is along the polarization direction, then the change is negligible,and the domains switched in the second half of the sine cycle cannot be recovered. The design of electric driving method needs to allow the use of a large applied field to emit strong enough signals and produce good images. This phenomenon combined with the coercive field increases with the driving frequency, thereby making the PMN-PT single crystals usable for high-frequency applications. As such, the applied field can be considerably larger than the conventionally defined coercive field.展开更多
PbTiO_(3)-based piezoelectric ceramics are key materials for developing various electromechanical transduc-ers.For high-power ultrasonic transducers,piezoelectric ceramics are required to possess large piezo-electric ...PbTiO_(3)-based piezoelectric ceramics are key materials for developing various electromechanical transduc-ers.For high-power ultrasonic transducers,piezoelectric ceramics are required to possess large piezo-electric coefficient(d_(33))and high mechanical quality factor(Q_(m)).Although acceptor dopants can im-prove Q_(m),they also deteriorate d_(33).If suitable piezoelectricity-beneficial donor dopants can be intro-duced into acceptor-doped ceramics,it is very possible to obtain large d_(33)and high Q_(m)simultaneously in donor and acceptor co-doped ceramics.In this work,a series of x mol%Sm and y mol%Mn co-doped Pb(Mg_(1/3)Nb_(2/3))O_(3)-30PbTiO_(3)(PMN-30PT:x Sm,y Mn)ceramics were prepared by the solid-phase sintered method.The crystal structure,local domain structure and electromechanical properties were sys-tematically analyzed.Optimal performances were obtained in PMN-30PT:2.5Sm,1-2Mn ceramics with d_(33)=860-543 pC/N,Q_(m)=495-754,and dielectric loss tanδ=0.0055-0.0086.This high performance origi-nates from the combined effects of(Mn″Ti−V_(o)^(••))^(×)defect dipoles and the local structural heterogeneity.展开更多
Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively...Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively high sintering temperature and low Curie temperature(T_(c))hinder their device applications.In this work,highly[001]_(c)-oriented(Ba_(0.95)Ca_(0.05))(Zr_(0.04)Ti_(0.96))O_(3) ceramics with x mol%CuO(x=0.25,0.5,1.0,2.5)denoted as BCZT-x were synthesized by templated grain growth using micro-sized raw powders.The introduction of CuO sintering agent lowered the sintering temperature by 125℃ to 1450℃,and the BCZT-1.0 achieved a high texture degree of∼99%.In addition,the CuO-based liquid phases eliminated boundaries between BT templates and BCZT matrix powders.Such liquid-phase sintering reduced sintering stresses,decreased the average grain size of BCZT-1.0 from 16μm down to 13μm,and increased the dielectric dispersion coefficientγto 1.63.The almost smoothed out T_(O-T) anomaly in the temperature dependence of dielectric permittivity and comparably high T_(c)(>102℃)lead to better temperature stability.The narrower grain orientation distribution with full width at half maximum(FWHM)of∼5.9°and smaller domains with the size of 0.1–0.5μm in width and 3–8μm in length were obtained,a high field induced maximum strain S_(max) of 0.38%and low H_(s) of 5.2%have been achieved in BCZT-1.0 textured ceramics together with a high and homogeneous piezoelectric stress coefficient d_(33)∼780 pC/N and very large d_(33)∗∼2950 pm/V.展开更多
Recently,the anomalous photovoltaic effect of ferroelectric materials has attracted considerable attention in the construction of efficient solar cells owing to the above-bandgap photovoltage of these materials.In thi...Recently,the anomalous photovoltaic effect of ferroelectric materials has attracted considerable attention in the construction of efficient solar cells owing to the above-bandgap photovoltage of these materials.In this study,we investigate the anomalous photovoltaic effect of relaxor-based ferroelectric Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)(PIMN-PT)ceramics with large remnant polarization and a narrow optical bandgap.Excellent photovoltaic performance with an ultrahigh open-circuit voltage of 23 V(575 V/cm)is achieved,which is higher than the open-circuit voltages of all reported polycrystalline materials with similar thickness.The phase structure,microstructure morphology,domain structure,ferroelectric and optical characteristics are analyzed,which could provide clues to the origin of the ultrahigh open-circuit voltage of PIMN-PT ceramics.The results suggest that the relaxor-based ferroelectric PIMNPT system is a potential candidate for photovoltaic solar energy conversion devices.展开更多
基金supported by the Natural Science Foundation of Heilongjiang Province(No.LH2021A012).
文摘Lead-free Bi_(_(0.5))Na_(_(0.5))TiO_(3)(BNT)piezoelectric ceramics have the advantages of large coercive fields and high Curie temperatures.But the improvement of piezoelectric coefficient(d 33)is usually accompanied by a huge sacrifice of depolarization temperature(T d).In this work,a well-balanced performance of d 33 and T d is achieved in MnO_(2)-doped 0.79(Bi_(_(0.5))Na_(_(0.5))TiO_(3))-0.14(Bi_(0.5)K_(0.5)TiO_(3))-0.07BaTiO_(3)ternary ceramics.The in-corporation of 0.25 mol%MnO_(2)enhances the d 33 by more than 40%,while T d remains almost unchanged(i.e.,d 33=181 pC/N,T d=184℃).X-ray diffraction(XRD)shows that an appropriate fraction of the small axis-ratio ferroelectric phase(pseudo-cubic,P c)coexists with the long-range ferroelectric phase(tetrag-onal,T)under this MnO_(2)doping.Piezoelectric force microscopy(PFM)has revealed a special domain configuration,namely large striped and layered macro domains embedded with small nanodomains.This study provides a distinctive avenue to design BNT-based piezoelectric ceramics with high piezoelectric performance and temperature stability.
基金Project supported by the Basic Scientific Research Foundation of College and University in Heilongjiang Province,China(Grant No.2018QNL-16)the Guiding Science and Technology Project of Daqing City(GSTPDQ),China(Grant No.zd-2019-03)the National Natural Science Foundation of China(Grant Nos.11304061 and 51572056).
文摘The influence of temperature on mode coupling effect in piezoelectric vibrators remains unclear.In this work,we discuss the influence of temperature on two-dimensional(2D)mode coupling effect and electromechanical coupling coefficient of cylindrical[001]c-poled Mn-doped 0.24PIN-0.46PMN-0.30PT piezoelectric single-crystal vibrator with an arbitrary configuration ratio.The electromechanical coupling coefficient kt decreases with temperature increasing,whereas k33 is largely invariant in a temperature range of 25℃-55℃.With the increase of temperature,the shift in the‘mode dividing point’increases the scale of the poling direction of the piezoelectric vibrator.The temperature has little effect on coupling constantΓ.At a given temperature,the coupling constantΓof the cylindrical vibrator is slightly greater than that of the rectangular vibrator.When the temperature changes,the applicability index(M)values of the two piezoelectric vibrators are close to 1,indicating that the coupling theory can be applied to piezoelectric vibrators made of late-model piezoelectric single crystals.
基金Project supported by the National Basic Research Program of China(973 Program)(2013CB632900)the National Natural Science Foundation of China(51472197)+2 种基金the Shaanxi Provincial Education Department(14JK1333)the Key Laboratory of Optoelectronic Materials Chemistry and Physics,Chinese Academy of Sciences(2016DP173016)Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices(2015SZSJ-59-5)
文摘Er^(3+)-modified 0.68 Pb(Mg_(1/3)Nb_(2/3))O_3-0.32 PbTiO_3(PMN-32 PT) single crystals were grown by using the flux method. The growth mechanism of the crystal and influences of Er^(3+) ions on phase structure,electrical and optical properties were investigated. Results reveal that the crystals are still pure perovskite structure with Er3+ ions doping, but lattice enlarges slightly. The coercive electric field is increased from 4.83 to 6.37 kV/cm for [100]-oriented crystals comparing to undoped PMN-32 PT single crystals.Moreover, the crystal exhibits upconversion emission properties. Green(531 and 552 nm) and red(670 nm) emission bands are recorded under the excitation of 980 nm diode laser, which correspond to the ~2 H_(11/2)→~4 I_(15/2), ~4 S_(3/2)→~4 I_(15/2) and ~4 F_(9/2)→~4 I_(15/2) transitions of Er^(3+) ions. Our results show the feasibility of using this crystal in photoelectric multifunctional devices.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674270)the Fundamental Research Funds for Xiamen University,China(Grant No.20720180113)+2 种基金the Education and Scientific Research Project for Young and Middle-aged Teachers of Fujian Province,China(Grant No.JAT170036)the Opening Fund of Acoustics Science and Technology Laboratory,China(Grant No.SSKF2018006)sponsored by the Education Department of Fujian Province,China for his study at the Pennsylvania State University(Grant No.2016071145)
文摘The [001]c-polarized(1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN-PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field( 2 kV/cm) of such crystals restricts their application at high frequencies because the driving field will exceed the coercive field. The depolarization field can be considerably larger in an antiparallel direction than in a parallel direction with respect to polarization when the bipolar driving cycle starts. Thus, if the direction of the sine wave signal in the first half cycle is opposite to the polarization direction, then the depolarized domains can be repolarized in the second half of the sine cycle. However, if the direction of the sine wave signal in the first half of the cycle is along the polarization direction, then the change is negligible,and the domains switched in the second half of the sine cycle cannot be recovered. The design of electric driving method needs to allow the use of a large applied field to emit strong enough signals and produce good images. This phenomenon combined with the coercive field increases with the driving frequency, thereby making the PMN-PT single crystals usable for high-frequency applications. As such, the applied field can be considerably larger than the conventionally defined coercive field.
基金This work was financially supported by the Natural Science Foundation of Heilongjiang Province(No.LH2021A012).
文摘PbTiO_(3)-based piezoelectric ceramics are key materials for developing various electromechanical transduc-ers.For high-power ultrasonic transducers,piezoelectric ceramics are required to possess large piezo-electric coefficient(d_(33))and high mechanical quality factor(Q_(m)).Although acceptor dopants can im-prove Q_(m),they also deteriorate d_(33).If suitable piezoelectricity-beneficial donor dopants can be intro-duced into acceptor-doped ceramics,it is very possible to obtain large d_(33)and high Q_(m)simultaneously in donor and acceptor co-doped ceramics.In this work,a series of x mol%Sm and y mol%Mn co-doped Pb(Mg_(1/3)Nb_(2/3))O_(3)-30PbTiO_(3)(PMN-30PT:x Sm,y Mn)ceramics were prepared by the solid-phase sintered method.The crystal structure,local domain structure and electromechanical properties were sys-tematically analyzed.Optimal performances were obtained in PMN-30PT:2.5Sm,1-2Mn ceramics with d_(33)=860-543 pC/N,Q_(m)=495-754,and dielectric loss tanδ=0.0055-0.0086.This high performance origi-nates from the combined effects of(Mn″Ti−V_(o)^(••))^(×)defect dipoles and the local structural heterogeneity.
基金This work was supported by the Postdoctoral Science Foundation(Nos.BX20490103,2020M681089,LBH-Z19065 and LBHZ13109)the National Natural Science Foundation of China(No.52002093).
文摘Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively high sintering temperature and low Curie temperature(T_(c))hinder their device applications.In this work,highly[001]_(c)-oriented(Ba_(0.95)Ca_(0.05))(Zr_(0.04)Ti_(0.96))O_(3) ceramics with x mol%CuO(x=0.25,0.5,1.0,2.5)denoted as BCZT-x were synthesized by templated grain growth using micro-sized raw powders.The introduction of CuO sintering agent lowered the sintering temperature by 125℃ to 1450℃,and the BCZT-1.0 achieved a high texture degree of∼99%.In addition,the CuO-based liquid phases eliminated boundaries between BT templates and BCZT matrix powders.Such liquid-phase sintering reduced sintering stresses,decreased the average grain size of BCZT-1.0 from 16μm down to 13μm,and increased the dielectric dispersion coefficientγto 1.63.The almost smoothed out T_(O-T) anomaly in the temperature dependence of dielectric permittivity and comparably high T_(c)(>102℃)lead to better temperature stability.The narrower grain orientation distribution with full width at half maximum(FWHM)of∼5.9°and smaller domains with the size of 0.1–0.5μm in width and 3–8μm in length were obtained,a high field induced maximum strain S_(max) of 0.38%and low H_(s) of 5.2%have been achieved in BCZT-1.0 textured ceramics together with a high and homogeneous piezoelectric stress coefficient d_(33)∼780 pC/N and very large d_(33)∗∼2950 pm/V.
基金financially supported in part by the NSFC(No.11304061,51572056 and 11974093)the National Key Basic Research Program of China(No.2013CB632900)。
文摘Recently,the anomalous photovoltaic effect of ferroelectric materials has attracted considerable attention in the construction of efficient solar cells owing to the above-bandgap photovoltage of these materials.In this study,we investigate the anomalous photovoltaic effect of relaxor-based ferroelectric Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)(PIMN-PT)ceramics with large remnant polarization and a narrow optical bandgap.Excellent photovoltaic performance with an ultrahigh open-circuit voltage of 23 V(575 V/cm)is achieved,which is higher than the open-circuit voltages of all reported polycrystalline materials with similar thickness.The phase structure,microstructure morphology,domain structure,ferroelectric and optical characteristics are analyzed,which could provide clues to the origin of the ultrahigh open-circuit voltage of PIMN-PT ceramics.The results suggest that the relaxor-based ferroelectric PIMNPT system is a potential candidate for photovoltaic solar energy conversion devices.