Lead zirconate titanate(PZT)ceramics are the most widely used commercial piezoelectric ceramics.However,the relationships between structure and properties are still not completely clarified.In this work,a broad invest...Lead zirconate titanate(PZT)ceramics are the most widely used commercial piezoelectric ceramics.However,the relationships between structure and properties are still not completely clarified.In this work,a broad investigation is carried out on commercial PZT 5A,5H and 4D ceramics.X-ray diffraction revealed that these compounds mainly contain a mixture of P4mm and C1m1 phases at room temperature,and poling induces an increased unit cell distortion in both phases and a higher content of the monoclinic phase.In the poled samples,the Curie point shifts towards lower temperatures,contradicting the Abrahams-Kurtz-Jamieson(AKJ)relation for distorted displacive ferroelectrics.The discordance in the phase transition behavior can be attributed to the decreased domain wall density in the PZT systems.Furthermore,the observed increase of the dielectric permittivity from radiofrequency to the THz range is explained by the increase of the ferroelectric distortion associated with the field-induced transitions and decreased domain wall density.A parameterψwas introduced to characterize the asymmetry of ferroelectric hysteresis loops.The higherψvalue of the hard PZT 4D ceramic compared to that of soft PZT 5A and 5H is attributed to the pinning effect of oxygen vacancies on domain walls.展开更多
Ferroelectric lead zirconate titanate(PZT,PbZr_(1−x)Ti_(x)O_(3))dominates the piezoelectric ceramic market because of its high piezoelectric coefficient,high thermal stability and low processing cost.Doping of PZT wit...Ferroelectric lead zirconate titanate(PZT,PbZr_(1−x)Ti_(x)O_(3))dominates the piezoelectric ceramic market because of its high piezoelectric coefficient,high thermal stability and low processing cost.Doping of PZT with lanthanum has been widely used to develop advanced piezoelectric ceramics with improved piezoelectric properties.However,the effects of La doping are ambiguous in the literature,and associated mechanisms are unclear.Here,we prepared La-doped PZT(PLZT)ceramics with different concentrations of La by the conventional solid-state reaction method.The PLZT ceramics have a perovskite structure,where tetragonal(P4mm)and monoclinic(C1m1)phases coexist.Upon La doping,the Curie point(Tc),ferroelectric lattice distortion,and concentration of oxygen vacancies decrease.Under an applied electric field,both domain switching and field-induced transition are observed.The remnant polarization(P_(r))of the doped PLZT ceramics is greater than that of the starting PZT ceramics,and the increased P_(r)is attributed to the substitution of reduced oxygen vacancies.With increasing temperature,the piezoelectric coefficient(d33)of the La-doped ceramics increases due to the increase in permittivity.The prevailing effect of high permittivity is related to the high d33 value(~375 pC/N)of the x=0.5 ceramics.These findings reveal the mechanisms associated with La doping in PZT ceramics,thereby providing a viable approach for developing advanced piezoelectric ceramics with high piezoelectric performance.展开更多
In this work,the dependency of the polarization(P)-electric field(E)loop area A of lead free ferro-electrics Na_(0.5)Bi_(0.5)TiO_(3)(NBT), K_(0.5)Bi_(0.5)TiO_(3)(KBT),and Na_(0.25)K_(0.25)Bi_(0.5)TiO_(3)(NKBT)on the a...In this work,the dependency of the polarization(P)-electric field(E)loop area A of lead free ferro-electrics Na_(0.5)Bi_(0.5)TiO_(3)(NBT), K_(0.5)Bi_(0.5)TiO_(3)(KBT),and Na_(0.25)K_(0.25)Bi_(0.5)TiO_(3)(NKBT)on the amplitude(E0)of the electric field is studied.Based on the nature of the hysteresis loop with increasing E0,the lnA versus lnE0 graph is divided into three stages and the scaling exponents of each stage are estimated.In the third stage,NBT,KBT,and NKBT show different shapes of P-E loops(square,slanted and pinched,respectively).Although,almost similar slopes in the third stage are obtained from the lnA versus lnE0 graphs of KBT and NKBT,the formation of pinched P-E loop of NKBT is discussed based on the current-time curve under a complete cycle of the applied electric field.The shape of the P-E loop also affects the recoverable energy storage density(Wrec)of the material.Similar to the scaling of A,the variation of lnWrec with lnE0 of NBT,KBT and NKBT are examined.Interestingly,three stages are only noticed in the lnWrec-lnE0 curve of pinched P-E loop(NKBT),whereas lnWrec linearly increases with lnE0 for square and slanted P-E loop.Such type of behavior of Wrec of NKBT is explained based on the reversible domain switching mechanism of the pinched P-E loop.展开更多
基金supported by the China Scholarship Council(No.202006040021)the Royal Society grant(NAF∖R1∖201126)+4 种基金the National Natural Science Foundation of China(Grant No.12404116)the Postdoctoral Fellowship Program of CPSF(GZC20232832)the Grant Agency of the Slovak Academy of Sciences(Grant VEGA No 2/0034/23)the Engineering and Physical Sciences Research Council(RC Grant reference:EP/Y027752/1)Foundation is gratefully acknowledged for an equipment grant(KAW 2003.0198)for the electron microscopy facilities at Stockholm University.
文摘Lead zirconate titanate(PZT)ceramics are the most widely used commercial piezoelectric ceramics.However,the relationships between structure and properties are still not completely clarified.In this work,a broad investigation is carried out on commercial PZT 5A,5H and 4D ceramics.X-ray diffraction revealed that these compounds mainly contain a mixture of P4mm and C1m1 phases at room temperature,and poling induces an increased unit cell distortion in both phases and a higher content of the monoclinic phase.In the poled samples,the Curie point shifts towards lower temperatures,contradicting the Abrahams-Kurtz-Jamieson(AKJ)relation for distorted displacive ferroelectrics.The discordance in the phase transition behavior can be attributed to the decreased domain wall density in the PZT systems.Furthermore,the observed increase of the dielectric permittivity from radiofrequency to the THz range is explained by the increase of the ferroelectric distortion associated with the field-induced transitions and decreased domain wall density.A parameterψwas introduced to characterize the asymmetry of ferroelectric hysteresis loops.The higherψvalue of the hard PZT 4D ceramic compared to that of soft PZT 5A and 5H is attributed to the pinning effect of oxygen vacancies on domain walls.
基金the China Scholarship Council for their financial support(Nos.202106370015,202006040021,and 202207000015)Krishnarjun Banerjee acknowledges the financial support from the Engineering and Physical Sciences Research Council(RC Grant reference:EP/Y027752/1)+1 种基金Vladimir Koval acknowledges the support of the Grant Agency of the Slovak Academy of Sciences(VEGA grant No.2/0034/23)the Slovak Research and Development Agency(APVV grant No.SK-CN-23-0014).
文摘Ferroelectric lead zirconate titanate(PZT,PbZr_(1−x)Ti_(x)O_(3))dominates the piezoelectric ceramic market because of its high piezoelectric coefficient,high thermal stability and low processing cost.Doping of PZT with lanthanum has been widely used to develop advanced piezoelectric ceramics with improved piezoelectric properties.However,the effects of La doping are ambiguous in the literature,and associated mechanisms are unclear.Here,we prepared La-doped PZT(PLZT)ceramics with different concentrations of La by the conventional solid-state reaction method.The PLZT ceramics have a perovskite structure,where tetragonal(P4mm)and monoclinic(C1m1)phases coexist.Upon La doping,the Curie point(Tc),ferroelectric lattice distortion,and concentration of oxygen vacancies decrease.Under an applied electric field,both domain switching and field-induced transition are observed.The remnant polarization(P_(r))of the doped PLZT ceramics is greater than that of the starting PZT ceramics,and the increased P_(r)is attributed to the substitution of reduced oxygen vacancies.With increasing temperature,the piezoelectric coefficient(d33)of the La-doped ceramics increases due to the increase in permittivity.The prevailing effect of high permittivity is related to the high d33 value(~375 pC/N)of the x=0.5 ceramics.These findings reveal the mechanisms associated with La doping in PZT ceramics,thereby providing a viable approach for developing advanced piezoelectric ceramics with high piezoelectric performance.
基金Author SA gratefully acknowledges the financial support pro-vided by the CSIR-EMRII(Ref.No.0194/NS)SERB,Department of Science and Technology(CRG/2020/001509)India to carry out this work.Author KB acknowledges DST-INSPIRE,India(Fellowship Code No.IF160462)for financial assistance.
文摘In this work,the dependency of the polarization(P)-electric field(E)loop area A of lead free ferro-electrics Na_(0.5)Bi_(0.5)TiO_(3)(NBT), K_(0.5)Bi_(0.5)TiO_(3)(KBT),and Na_(0.25)K_(0.25)Bi_(0.5)TiO_(3)(NKBT)on the amplitude(E0)of the electric field is studied.Based on the nature of the hysteresis loop with increasing E0,the lnA versus lnE0 graph is divided into three stages and the scaling exponents of each stage are estimated.In the third stage,NBT,KBT,and NKBT show different shapes of P-E loops(square,slanted and pinched,respectively).Although,almost similar slopes in the third stage are obtained from the lnA versus lnE0 graphs of KBT and NKBT,the formation of pinched P-E loop of NKBT is discussed based on the current-time curve under a complete cycle of the applied electric field.The shape of the P-E loop also affects the recoverable energy storage density(Wrec)of the material.Similar to the scaling of A,the variation of lnWrec with lnE0 of NBT,KBT and NKBT are examined.Interestingly,three stages are only noticed in the lnWrec-lnE0 curve of pinched P-E loop(NKBT),whereas lnWrec linearly increases with lnE0 for square and slanted P-E loop.Such type of behavior of Wrec of NKBT is explained based on the reversible domain switching mechanism of the pinched P-E loop.
