Electromechanical-induced antiferroelectric-ferroelectric phase transition in PbLa(Zr,Sn,Ti)O_3 ceramic

Antiferroelectric ferroelectric （AFE-FE） phase transition in ceramic Pbo.97Lao.02（Zro.75Snon36Tion14）O3 （PLZST） was studied by dielectric spectroscopy as functions of frequency （102-105 Hz） and pressure （0-500 MPa） under a DC electric field. The hydrostatic pressure-dependent remnant polarization and dielectric constant were mea- sured. The results show that remnant polarization of the metastable rhombohedral ferroelectric PLZST poled ceramic decreases sharply and depoles completely at phase transition under hydrostatic pressure. The dielectric constant um dergoes an abrupt jump twice during a load and unload cycle under an electric field. The two abrupt jumps correspond to two phase transitions, FE AFE and AFE-FE.

FABRICATION AND PROPERTIES OF ANTIFERROELECTRIC RAINBOW ACTUATOR

A new type of large-displacement actuator called reduced and internally biased oxide wafer （RAINBOW） is fabricated by chemical reduction of Pb（Sn, Zr, Ti）O3（PSZT） antiferroelectric ceramics and its properties are investigated. It is found that PSZT is easily reduced and the optimal conditions for producing RAINBOW samples are determined to be 870 ℃ for 2-3 h. The antiferroelectrics-ferroelectrics phase transitions occur at lower field strength in RAINBOW actuators compared with normal PSZT actuators. Large axial displacements are also obtained from the RAINBOW actuator by application of electric fields exceeding the phase switching level. However, the field-induced displacement of the RAINBOW actuator is dependent on the manner of applying load on the samples.

Energy storage performance and phase transition under high electric field in Na/Ta co-doped AgNbO_(3)ceramics

Lead-free antiferroelectric ceramics with high energy storage performance show great potential in pulsed power capacitors.However,poor breakdown strength and antiferroelectric stability are the two main drawbacks that limit the energy storage performance of antiferroelectric ceramics.Herein,highquality(Ag_(1-x)Na_(x))(Nb_(1-x)Ta_(x))O_(3)ceramics were prepared by the tape casting process.The breakdown strength was greatly improved as a result of the high density and fine grains,while the antiferroelectric stability was enhanced owning to the M2 phase.Benefiting from the synergistic improvement in breakdown strength and antiferroelectric stability,(Ag_(0.80)Na_(0.20))(Nb_(0.80)Ta_(0.20))O_(3)ceramic reveals a benign energy storage performance of W_(rec)=5.8 J/cm^(3)and h=61.7%with good temperature stability,frequency stability and cycling reliability.It is also found that the high applied electric field can promote the M2-M3 phase transition,which may provide ideas to improve the thermal stability of the energy storage performance in AgNbO_(3)-based ceramics.

Effect of temperature on phase transition behavior of antiferroelectric (Pb_(0.97)La_(0.02) )(Zr_(0.75)Sn_(0.25-x)Ti_x)O_3 ceramics

Pb0：97La0：02（Zr0：75Sn0：25x Ti x/O3（x D0.10, 0.105, 0.11）（PLZST） antiferroelectric ceramics with highly preferred-（110） orientation were successfully fabricated via the conventional solid-state reaction method.The antiferroelectric nature of PLZST ceramics induced by electric field was demonstrated by the dielectric constant-temperature（D-T） and the polarization-electric field（P-E） measurement. Typical phase transition from ferroelectric（FE） to antiferroelectric（AFE）, and then to paraelectric（PE） is obtained. The results indicate that the phase transition behavior is suppressed with increasing of x, and T c is remarkably shifted to higher temperature of168 ℃, 170 ℃ and 174 ℃, respectively. Besides, high phase transition current（110 6A, 810 7A and 610 7A, respectively） is obtained with temperature induced. Consequently, the excellent electric properties and the restraint between temperature and electric field would provide basis on the application of PLZST antiferroelectric ceramics in microelectronic integrated systems and sophisticated weapons systems.

Release of charges under external fields of PbLa(Zr,Sn,Ti)O_3 ceramic

This paper investigates the pyroelectric of poled antiferroelectric （AFE） ceramic Pbo.97Lao.02 （Zro.69Sno.196 Ti0.114）03 and its remnant polarization dependence of hydrostatic pressure. The results show that the bound charges of poled sample can be released in short time by temperature field or pressure field. The released charge abruptly forms a large pulse current. The phenomena of released charge under external fields result in the ferroelectric-AFE phase transition induced by temperature or hydrostatic pressure.

Study of RAINBOW Actuators Made of PSZT

A new type of large\|displacement actuator called RAINBOW (Reduced And Internally Biased Oxide Wafer) was fabricated by a chemical reduction of PSZT antiferroelectric ceramic. It is found that PSZT was easily reduced and the optimal conditions for producing RAINBOW samples were determined to be 870℃ for 2~3 h. The AFE\|FE phase transitions occur at lower field strength in RAINBOWs compared with normal PSZT. Larger axial displacement (about 190μm) was obtained from the RAINBOWs by application of electric ...

Enhanced energy storage properties and antiferroelectric stability of Mn-doped NaNbO_(3)-CaHfO_(3) lead-free ceramics:Regulating phase structure and tolerance factor

NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is not conducive to energy storage applications.Our previous work found that incorporating CaHfO_(3) into NaNbO_(3) can stabilize its antiferroelectric phase by reducing the tolerance factor(t),as indicated by the appearance of characteristic double P-E loops.Furthermore,a small amount of MnO_(2) addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO_(3)-0.06CaHfO_(3)(0.94NN-0.06CH),which can further improve the stability of antiferroelectricity.The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO_(2).The antiferroelectric orthorhombic phase first increases and then decreases,while the t shows the reversed trend,thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm^(3) at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO_(2)(in mass fraction).With the increase of Mn content to 1.0%from 0.5%,the efficiency increases to 81% from 45%,although the energy storage density decreases to 1.31 J/cm^(3) due to both increased tolerance factor and non-polar phase.