Field-induced Strain Behavior Research Articles

Field-induced strain engineering to optimize antiferroelectric ceramics in breakdown strength and energy storage performance

The unique filed-induced phase transition makes antiferroelectric (AFE) ceramics naturally advantageous in exploiting advanced capacitors with ideal energy storage performance. However, low breakdown strength (BDS) has become one key restriction on energy storage performance of AFE ceramic and there have fewer research been carried out focused on optimizing breakdown strength with the design strategy based on regulating field-induced strain behavior. Here, we first propose introducing Nd3+ to induce incommensurate modulated AFE phase in Pb0.98Sr0.02Zr0.75Sn0.25O3 (PSrZS) matrix. Benefited from this strategy, the field-induced strain was well dispersed that the strain rate under electric field (strain/electric field) significantly decreased. Accordingly, inducing incommensurate modulated AFE phase in matrix by introducing Nd3+ greatly enhanced the BDS from 350 kV/cm to 540 kV/cm by regulating strain behavior combined with the delayed saturated polarization and significantly optimized several key parameters including hysteresis width and phase-switching field. As a result, outstanding recoverable energy density of 14.21 J/cm3 accompanying with high efficiency of 87.35% were obtained in 0.03 Nd-doped PSrZS ceramics at 530 kV/cm at room temperature. The actual discharge performance is also prominent. Ultrahigh current density of 2111 A/cm2 and power density of 507 MW/cm3 were obtained in PSrNd0.03ZS ceramics. The sample also exhibited a high discharge energy density of 9.11 J/cm3. The great energy storage properties obtained in this work provides a novel strategy to further enhance the energy storage performance and demonstrates the extremely potential of AFE ceramics in exploiting advanced ceramic capacitors for pushing on the miniaturization and integration of electronic devices.

Lead-based antiferroelectrics revisited for high energy density capacitors and large strain actuators

Lead zirconate stannate titanate (PZST) ceramics with the generic composition of Pb1-0.5xNbx[(ZrySn1-y)1-zTiz]1-xO3 with x representing Nb content (x = 0 or 0.02), y representing Zr:Sn ratio (y = 0.57 or 0.60), and z representing Ti content (z = 0.06 or 0.08), and lead lanthanum zirconate titanate (PLZT) ceramics with the general composition of Pb1-xLax(ZryTi1−y)1−x/4O3 with x = 0.050 − 0.120 were synthesized using solid state reaction method and sintering. The energy density and field induced strain behavior of these compositions were investigated for capacitor and actuator applications, respectively. The focus of the study was to evaluate and discuss the change in the polar state of these ceramics from normal ferroelectric to antiferroelectric to relaxor antiferroelectric to linear dielectric with compositional modification. The highest releasable energy density (1.053 J/cm3) was obtained from the antiferroelectric Pb[(Zr0.60Sn0.40)0.94Ti0.06]O3 composition among the PZST compositions that were investigated, but the efficiencies were generally low (max. 60%) due to the large hysteresis that was observed in these compositions. The highest field induced strain level of 0.26% was also measured in the same composition. In the case of PLZT compositions, the highest releasable energy density values (0.313 J/cm3) with much higher efficiencies (76%) and highest field induced strain levels (0.23%) were obtained from the PLZT compositions with relaxor antiferroelectric character.

An investigation of structural, electrical and optical properties of lead-free barium zirconium titanate (BZT)-based ceramic compounds

ABSTRACT The present work is a demonstration of improved electrical and optical properties of barium zirconium titanate ceramic modified by the addition of Europium, i.e. Ba(1–x)Eu2x/3Zr0.05Ti0.95O3 (x = 0.01, 0.02, 0.03, 0.04). The Rietveld refinement studies confirmed the formation of tetragonal phase in the samples. The scanning electron microscopy (SEM) images revealed a decrease in grain size with increasing Eu concentration. The dielectric constant, dielectric loss and TCC plots are drawn to study temperature and frequency dependence of the samples. The electric field-induced strain behavior has been studied for all the compositions of the synthesized ceramic at room temperature. Conduction mechanism in the samples as a function of frequency and temperature was studied with the help of AC conductivity data. Also, the effect of grain and grain boundaries are studied in term of Cole–Cole plots. Photoluminescence (PL) emission spectra were recorded upon excitation with a wavelength of 360 nm.

Gaint electric field-induced strain and ferroelectric behavior of Bi0.5Na0.4K0.1TiO3-Na1-xLixNbO3 lead-free ceramics

0.96 Bi0.5Na0.4K0.1TiO3-0.04Na1-xLixNbO3 (BNKT-100xLi, x = 0, 0.25, 0.5, 0.75, 1.0) lead-free ceramics were prepared using traditional solid-state reaction method. X-ray diffraction patterns confirmed the pure perovskite structure of sintered ceramics. Electric field and composition-dependent strain behavior was investigated. The highest bipolar strain of 0.45% and the unipolar strain 0.443% was achieved at x = 0.75 under the applied electric field of 70 kV/cm. Meanwhile, the corresponding normalized strain (d33*) reached to 633 pm/V. Moreover, the giant strain exhibited excellent thermal stability and fatigue-resistance (within 105 switching cycles) properties, and the large strain was attributed to the reversible electric field-induced transition between relaxor and ferroelectric phase.

Large reversible magnetic-field-induced strain in a trained Ni49.5Mn28Ga22.5 polycrystalline alloy

The magnetic-field-induced strain (MFIS) is investigated in a directionally solidified Ni-Mn-Ga polycrystalline alloy. A 0.2% reversible MFIS is achieved after superelastic training, which is a large value as reported in polycrystalline samples without any external stress. Such prominent behavior is attributed to the oriented internal stress induced by superelastic training. On the basis of the phase-field simulation combined with experimental studies, the field induced strain behavior and the underlying microstructure evolution of Ni-Mn-Ga polycrystalline alloy are studied. The results show that the preferential orientation of martensite variants formed by the oriented internal stress is responsible for the large reversible MFIS. It is demonstrated that superelastic training would be an effective processing way to improve the MFIS in polycrystalline Ni-Mn-Ga alloys.

Sr(Zn1/3Nb2/3)O3-induced R3c to P4bm transition and large field-induced strain in 0.80(Bi0.5Na0.5)TiO3–0.20SrTiO3 ceramics

Abstract

Giant strain of 0.65% obtained in B-site complex cations (Zn1/3Nb2/3)4+-modified BNT-7BT ceramics

A giant field-induced strain of 0.65% with excellent temperature insensitivity and fatigue resistance was achieved by introducing 1.5 mol.% B-site complex cations (Zn1/3Nb2/3)4+ into the 0.93(Bi1/2Na1/2)TiO3-0.07BaTiO3 lead-free ferroelectric ceramics. (Bi1/2Na1/2)0.93Ba0.07(Zn1/3Nb2/3)xTi1-xO3 (0 ≤ x ≤ 0.025) ceramics were prepared by the columbite route, their microstructure, electric properties, and field-induced strain behavior were systematically investigated. XRD analysis reveals that the B-site substitution by complex cations (Zn1/3Nb2/3)4+ induces the phase transition from R3c to pseudocubic structures, and demonstrates different phase evolution under field applied. At the composition x = 0.015, a composition-driven boundary between the nonergodic state and ergodic state is observed. Meanwhile, the substitution by complex cations (Zn1/3Nb2/3)4+ reduces the dimension of polar nanoregions (PNRs) due to the destruction of the long-range ferroelectric ordering. A phenomenological illustration based on Bokov's suggestion and Landau-Devenshire theory suggests the relationship between the size of PNRs and field-induced strain behavior.

Electric field–induced strain behavior and ferroelectric properties of lead zirconate titanate-barium calcium zirconate titanate ceramics

ABSTRACTIn this work, electric field-induced strain behavior and ferroelectric properties of xBCZT/PZT (with x = 0, 4 and 8 mol%) ceramics have been investigated. The Ec and Pr increased with increasing electric field and exhibited pinched-shape hysteresis loop at 60 kV/cm. The abnormal domain walls and switching behavior of the domains were used to discuss the above results. The strain value increased with increasing BCZT content and reached the maximum value of 0.27% (d*33 = 450 pm/V) for the 4 mol% BCZT sample. This offered an opportunity to obtain a good candidate for using in piezoelectric applications.

Phase structure and electromechanical behavior of Li, Nb co-doped 0.95Bi0.5Na0.5TiO3–0.05BaZrO3 ceramics

Abstract In this work, the effect of Li, Nb co-doping on the structural phase, dielectric, ferroelectric and field induced strain behavior of 0.95Bi 0.5 Na 0.5 TiO 3 –0.05BaZrO 3 (BNT-BZ5) ceramic was investigated. X-ray diffraction patterns revealed the formation of single phase perovskite structure in the studied composition range. However, with increasing Li, Nb co-doping concentration, the maximum dielectric constant decreased and the dielectric maximum temperature ( T m ) slightly shifted towards higher temperature. The field induced strain response increased from 0.18% for pure BNT-BZ5 to 0.38% for 1 mol.% Li, Nb modified BNT-BZ5 sample. The corresponding dynamic piezoelectric coefficient for these composition were ( S max / E max = 257 pm/V) and ( S max / E max = 542 pm/V), respectively. These results suggest that the BNLTN–BZ ceramic can be considered as a promising candidate material for piezoelectric application.

Influence of low external magnetic field on electric field induced strain behavior of 9/70/30, 9/65/35 and 9/60/40 PLZT ceramics

In this work, Pb0.91La0.09(ZrxTi1−x)0.9775O3 PLZT ceramics, where x =0.70, 0.65 and 0.60, were prepared by a solid-state mixed-oxide technique. Structural information was investigated by X-ray diffraction method. Electric field induced polarization and strain behavior of the PLZT ceramics under an influence of static magnetic field were measured by a Sawyer-Tower circuit in conjunction with Michelson interferometer at various static magnetic fields (0–30.7mT). The results showed that the imposed magnetic field affected the polarization and induced strain behaviors in PLZT ceramics More interestingly, the imposed magnetic field showed more significant influence on the PLZT ceramic composition near morphotropic phase boundary (MPB), i.e. PLZT 9/65/35. The spontaneous polarization of 180° domain switching was seen to be suppressed by the applied magnetic field.

Dielectric, ferroelectric and induced strain behavior of PLZT 9/65/35 ceramics modified by Bi2O3 and CuO co-doping

PLZT 9/65/35 (Pb0.91La0.09(Zr0.65Ti0.35)0.9775O3) ceramics with addition of 0.25, 0.5 and 1.0wt% of Bi2O3/CuO (where the ratio of Bi2O3:CuO=9:1 by mole) were prepared by sintering at the temperatures between 1000 and 1200°C. It was found that Bi2O3/CuO could bring the sintering temperature down ~50°C to obtain PLZT with no second phase. Dielectric and ferroelectric properties were investigated. Bi2O3/CuO decreased both coercive field and remnant polarization, which was caused by an increase of the degree of diffuseness in relaxor ferroelectric materials. Electric field induced strain behavior was also investigated and it was found that the addition of Bi2O3/CuO increased the maximum induced strain and maximized electrostrictive effect. Therefore, Bi2O3/CuO was useful as a sintering aid, which improved the dielectric and the relaxor ferroelectric properties as well as the electric field induced strain of PLZT ceramics.

Lead‐Free (Ba0.70Sr0.30)TiO3‐Modified Bi0.5(Na0.80K0.20)0.5TiO3 Ceramics with Large Electric Field–Induced Strains

The dielectric, ferroelectric, and electric field–induced strain behavior of Bi0.5(Na0.80K0.20)0.5TiO3 (BNKT) ceramics modified with (Ba0.70Sr0.30)O3 (BST) were investigated as a function of composition and temperature. The ceramic samples were synthesized by a solid‐state mixed oxide method and sintered at 1125°C for 2 h. The XRD and Raman spectra showed coexisting rhombohedral and tetragonal phases throughout the entire compositional range with the tetragonal phase becoming dominant at higher BST concentrations. For all compositions, the temperature dependence of the dielectric spectra revealed a frequency dependence that is characteristic of a relaxor mechanism. This suggests that these ceramics lacked long‐range order and it appears that the maximum disorder was observed for the composition with 5 mol% BST (BNKT–0.05BST sample). This was evidenced by the observation of pinched hysteresis loops, even at room temperature, and a significant decrease in the Pr and Ec values which resulted in large electric field–induced strains (Smax) of 0.40% and a normalized strain coefficient ( = Smax/Emax) of 732 pm/V. This significant strain enhancement at the composition of x = 0.05 may be attributed to both a composition‐induced structural phase transition and a field‐induced relaxor to ferroelectric phase transition.

Enhanced electric field-induced strain and ferroelectric behavior of (Bi0.5Na0.5)TiO3–BaTiO3–SrZrO3 lead-free ceramics

The crystal structure, electric field-induced strain (EFIS) and piezoelectric properties of lead-free SrZrO3-modified Bi0.5Na0.5TiO3–0.065BaTiO3 (BNBT–SZ100x, with x=0–10) ceramics were investigated. The X-ray diffraction analysis revealed a phase transformation from tetragonal to pseudocubic symmetry with increasing amounts of SZ. A large EFIS of 0.39% was obtained at the critical composition of BNBT–SZ2 which corresponds to a normalized strain (Smax/Emax) of 722pm/V at a low applied field of ~5.5kV/mm. Ferroelectric curves indicated a disruption of ferroelectric order and a decrease in the remnant polarization and coercive field. A maximum value of piezoelectric constant (197pC/N) and electromechanical coupling coefficient (29.4%) was obtained for SZ1 ceramics. The maximum dielectric constant temperature (Tm) and depolarization temperature (Td) shifted towards lower temperatures and curves became more diffuse with increasing amounts of SZ. The results indicate that BNBT–SZ100x ceramics can be promising candidates for lead-free actuators.

Dielectric, ferroelectric and electric field-induced strain behavior of Ba(Ti0.90Sn0.10)O3-modified Bi0.5(Na0.80K0.20)0.5TiO3 lead-free piezoelectrics

Lead-free piezoelectric ceramics of (1−x)Bi0.5(Na0.80K0.20)0.5TiO3–xBa(Ti0.90Sn0.10)O3 or (1−x)BNKT–xBTS (when x=0–0.20mol fraction) were investigated. Optimum sintering temperature was found to be 1125°C at which all compositions had relative densities 98–99% of their theoretical values. All compositions exhibited a single perovskite structure. The unit cell size expansion was observed as BTS content increased. A slight reduction of grain size was noticeable when small amount of BTS was added. The BNKT–0.05BTS sample had a large electric field-induced strain (Smax) of 0.36% which corresponded to the normalized strain coefficient (d33∗) of 649pm/V. The highest piezoelectric coefficient (d33=215pC/N) with good dielectric (ɛr=1721, tanδ=0.0724 and Tc=333°C) and ferroelectric properties (Pr=20.49μC/cm2, Rsq=0.87) were obtained for BNKT–0.10BTS sample, suggesting that this composition had a potential to be one of the promising lead-free piezoelectric candidates for further use in actual applications.

Field induced strain response of lead-free BaZrO3-modified Bi0.5Na0.5TiO3–BaTiO3 ceramics

Lead-free (0.935−x)[Bi0.5Na0.5TiO3–0.065BaTiO3]–xBaZrO3 (BNBT–xBZ, with x=0−0.07) ceramics were prepared by a conventional solid-state reaction method. The effect of BZ addition on the crystal structure, microstructure, dielectric, ferroelectric and electric field induced strain behavior of BNBT ceramic was investigated. X-ray diffraction patterns of BNBT–xBZ ceramics revealed the formation of single phase perovskite structure in the studied composition range. Addition of BZ in BNBT transform the crystal structure from tetragonal to pseudocubic symmetry. However, with increasing BZ content, the maximum dielectric constant decreased and the dielectric maximum temperature (Tm) shifted towards lower temperature. The field induced strain response of BNBT–xBZ increases from 0.16% for x=0 to 0.38% for x=0.03, at an applied field of 7kV/mm. The corresponding dynamic piezoelectric coefficient for these composition were (Smax/Emax=231pm/V) and (Smax/Emax=542pm/V), respectively. These results suggest that the BNBT–0.03BZ ceramic can be considered as a promising candidate material for piezoelectric application.

Compositional dependence of dielectric and ferroelectric properties in BiFeO3–BaTiO3 solid solutions

Polycrystalline (1−x)BiFeO3–xBaTiO3 (0.11≤x≤0.5) ceramics have been prepared by the solid-state reaction method to investigate their phase structure, dielectric, ferroelectric, and field-induced strain behaviors. The phase was found to change from rhombohedral in BiFeO3-rich compositions to pseudocubic at a BaTiO3 content of x=0.33. The room-temperature dielectric permittivity increased with increasing BaTiO3 content regardless of phase structure, except for a small dielectric permittivity peak additionally observed at x=0.33. The (1−x)BiFeO3–xBaTiO3 solid solutions displayed a maximum in permittivity at temperatures (Tm) above 300°C in the compositional range of 0.2≤x≤0.5. The frequency dependence of high-temperature dielectric properties suggests that BiFeO3–BaTiO3 is a relaxor ferroelectric. Normal ferroelectric loops and large electric field-induced strains were observed for the BiFeO3–BaTiO3 ceramics. The BiFeO3–BaTiO3 shows a promising candidate for high temperature ferroelectric applications.

Effect of Nd3+ substitution on electric field induced strain behavior in lead zirconate stannate titanate (68/22/10) ceramics

Abstract Pb 1−3 x /2 Nd x (Zr 0.68 Sn 0.22 Ti 0.1 )O 3 ceramics with large electrical field induced strain were prepared by Nd 3+ doping. X-ray diffraction analysis showed that the substitution of Nd 3+ for Pb 2+ enhanced the stability of antiferroelectric phase due to the decrease of tolerance factor. Besides, with the increase of Nd 3+ addition, the strain first improved with a maximum value at x = 0.02, and then decreased. Further, with increasing electric field and decreasing measuring frequency, the strain improved obviously. This is because that the reversal of the domains is more sufficient at large electric field and long time. The largest strain of 0.63% is obtained in the specimens with x = 0.02 at the frequency 1 Hz.

Effect of PMN content on the phase structure and electrical properties of PMN–PZT ceramics

Abstract x Pb(Mg 1/3 Nb 2/3 )O 3 –(1− x )Pb(Zr 0.47 Ti 0.53 )O 3 ( x PMN–(1− x )PZT) (0.15≤ x ≤0.30) ceramics were prepared by the conventional oxide-mixed method. The phase structure, ferroelectric and piezoelectric properties and field-induced strain behavior were systematically investigated. It was found that 0.25PMN−0.75PZT possessed superior electrical properties due to its composition close to the MPB (Morphotropic Phase Boundary). The composition near the MPB enables the existence of multiple polarization directions and consequently facilitates the domain reorientation, which should be responsible for the superior electrical properties. A large remnant polarization ( P r ) of 34.2 µC/cm 2 and a high piezoelectric coefficient ( d 33 ) of 698 pC/N were obtained. Especially, a large field-induced strain of 2.2‰ (at 40 kV/cm) was attained, which shows a great promise for actuator applications.

Influence of zirconium substitution on dielectric, ferroelectric and field-induced strain behaviors of lead-free 0.99[Bi1/2(Na0.82K0.18)1/2(Ti1−x Zr x )O3]-0.01LiSbO3 ceramics

The Crystal structure, dielectric, ferroelectric and field-induced strain behaviors of lead-free 0.99[Bi1/2(Na0.82K0.18)1/2(Ti1−xZrx)O3]-0.01LiSbO3 (BNKTZ-LS) ceramics were investigated in the composition range x = 0 − 0.040. XRD patterns revealed the formation of a pure perovskite phase with no apparent structural phase transition. The temperature-dependent dielectric peaks of the BNKTZ-LS ceramics broadened and the ferroelectric polarizations decreased with increasing Zr concentration. Ferroelectric and bipolar field induced-strain curves indicated a disruption of ferroelectric order upon Zr addition into the BNKT-LS ceramics. This destabilization of the ferroelectric order was accompanied by an enhanced field-induced strain. A high field-induced strain (S = 0.30%) with a normalized strain (d*33 = Smax/Emax = 500 pm/V) was observed at an applied electric field of 6 kV/mm at x = 0.020.

Dielectric, ferroelectric and field-induced strain behavior of K0.5Na0.5NbO3-modified Bi0.5(Na0.78K0.22)0.5TiO3 lead-free ceramics

Lead-free piezoelectric (1−x)Bi0.5(Na0.78K0.22)0.5TiO3–xK0.5Na0.5NbO3 (BNKT–xKNN, x=0–0.10) ceramics were synthesized using a conventional, solid-state reaction method. The effect of KNN addition on BNKT ceramics was investigated through X-ray diffraction (XRD), dielectric, ferroelectric and electric field-induced strain characterizations. XRD revealed a pure perovskite phase with tetragonal symmetry in the studied composition range. As the KNN content increased, the depolarization temperature (Td) as well as maximum dielectric constant (ɛm) decreased. The addition of KNN destabilized the ferroelectric order of BNKT ceramics exhibiting a pinched-type hysteresis loop with low remnant polarization (11μC/cm2) and small piezoelectric constant (27pC/N) at 3mol% KNN. As a result, at x=0.03 a significant enhancement of 0.22% was observed in the electric field-induced strain, which corresponds to a normalized strain (Smax/Emax) of ∼434pm/V. This enhancement is attributed to the coexistence of ferroelectric and non-polar phases at room temperature.