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Relaxor ferroelectrics show substantial responses to electric fields. The key difference from normal ferroelectrics is a temperature-dependent inhomogeneous structure and its dynamics. The lead-based complex perovskite Pb(In1/2Nb1/2)O3 is an intriguing system in which the inhomogeneous structure can be controlled by thermal treatment. Herein, we report investigations of the phase transitions in single crystals of Pb(In1/2Nb1/2)O3 via changing the degree of randomness in which In and Nb occupy the B site of the ABO3 perovskite structure. We studied the dynamic properties of the structure using inelastic light scattering and the static properties using diffuse X-ray scattering. These properties depend on the degree of randomness with which the B site is occupied. When the distribution of occupied In/Nb sites is regular, the antiferroelectric phase is stabilised by a change in the collective transverse-acoustic wave, which suppresses long-range ferroelectric order and the growth of the inhomogeneous structure. However, when the B site is occupied randomly, a fractal structure grows as the temperature decreases below T*~475 K, and nanosized ferroelectric domains are produced by the percolation of self-similar and static polar nanoregions.

The CXD method have been shown to be applicable to the crystal characterization as well as the domain observation. The present CXD technique could evaluate the crystal coherence length up to 10 μm ...

We have investigated the effect of $B$-site randomness on the antiferroelectric/relaxor nature of the ground state by studying diffuse and inelastic x-ray scattering from ordered and disordered $\mathrm{Pb}({\mathrm{In}}_{1/2}{\mathrm{Nb}}_{1/2}){\mathrm{O}}_{3}$ (O- and D-PIN) single crystals. The diffuse scattering measurement of O-PIN, which is antiferroelectric at low temperatures, shows that the ferroelectrically interactive local polarization exists in the cubic phase, above the transition temperature ${T}_{\mathrm{N}}$. Inelastic x-ray scattering analysis of the diffuse scattering shows that the transverse-acoustic (TA) and transverse-optic (TO) modes are dominant at high temperatures ($\ensuremath{\sim}800$ K), while the central peak (CP) and TA modes, which are coupled, contribute majorly to diffuse scattering near ${T}_{{}_{\mathrm{N}}}$ and show critical behavior at temperature close to ${T}_{{}_{\mathrm{N}}}$. The TO mode shows no anomaly at temperature close to ${T}_{{}_{\mathrm{N}}}$. Furthermore, the phonon spectra are broad, indicating that a strong damping mechanism exists even in the sample with weak chemical disordering, O-PIN. No clear difference between O- and D-PIN is observed at temperatures above $\ensuremath{\sim}500$ K. Here, the major difference between them is the property of the CP mode, which shows no drop and increases rapidly with decreasing temperatures in D-PIN. The CP mode is thought to be directly related to the local polarization and to originate in a combination of Pb flipping and the TO mode. The $B$ site is considered to control the antiferroelectric/ferroelectric instability of lead-based perovskite materials. Finally, the $B$-site randomness is discussed in terms of suppressing the antiferroelectric instability and enhancing the polarization fluctuation.

Relaxor ferroelectrics show substantial responses to electric fields. The key difference from normal ferroelectrics is a temperature-dependent inhomogeneous structure and its dynamics. The lead-based complex perovskite Pb(In1/2Nb1/2)O3 is an intriguing system in which the inhomogeneous structure can be controlled by thermal treatment. Herein, we report investigations of the phase transitions in single crystals of Pb(In1/2Nb1/2)O3 via changing the degree of randomness in which In and Nb occupy the B site of the ABO3 perovskite structure. We studied the dynamic properties of the structure using inelastic light scattering and the static properties using diffuse X-ray scattering. These properties depend on the degree of randomness with which the B site is occupied. When the distribution of occupied In/Nb sites is regular, the antiferroelectric phase is stabilised by a change in the collective transverse-acoustic wave, which suppresses long-range ferroelectric order and the growth of the inhomogeneous structure. However, when the B site is occupied randomly, a fractal structure grows as the temperature decreases below T *~475 K, and nanosized ferroelectric domains are produced by the percolation of self-similar and static polar nanoregions.

We employed Raman scattering and x-ray diffraction to investigate the behavior of disordered perovskite-type Pb(In1/2Nb1/2)O3 (PIN) under high pressure up to 50 GPa at 300 K. The sharp peak centered at 380 cm−1 increases its intensity with pressure. Two Raman peaks around 550 cm−1 merge at 16 GPa and their linewidths increase with pressure. The structural phase transition is associated with a splitting of the 50 cm−1 peak above 16 GPa. The pressure evolution of the diffraction patterns for PIN shows obvious splitting above 16 GPa and 33 GPa, particularly for the pseudo-cubic (110), (200), and (211) diffraction peaks, indicative of a symmetry-lowering transition. Our results demonstrate that PIN undergoes successive structural phase transitions: a pseud-cubic to orthorhombic at 0.5 GPa; a transition from orthorhombic to orthorhombic at 16 GPa due to enhanced octahedra tilting and change in linear compressibility; the transition at 33 GPa is plausibly a transition to a monoclinic phase.

Electromechanical properties of 0.5Pb(Ni1/3Nb2/3)O3-0.5Pb(Zr0.7Ti0.3)O3 (0.5PNN-0.5PZT(0.7/0.3)) ceramics near a morphotropic phase boundary were investigated under the hydrostatic pressure p up to 600 MPa at room temperature, where the piezoelectric constants d33 = 850 pC/N and d31 = 332 pC/N were obtained in this material. The remarkable change in the pressure dependence of the electromechanical response was found, where the resonance and antiresonance curves in impedance and phase in k31 mode for the transverse electromechanical property of 0.5PNN-0.5PZT(0.7/0.3) decrease with increasing pressure, and disappear completely at about p = 600 MPa. It was also confirmed that after removal of applied pressures, the electromechanical response recovers. Accompanied with such suppression of piezoelectric response, the increase in 30% of the permittivity ϵr with increasing p, was observed.

Rhombohedral ellipsoidal domains, tetragonal circular ones, orthorhombic star ones, and dark domains consisted of fluxes of platelets were found to be induced on the (001)cub plane in 24PIN-46PMN-30PT crystals by shear stresses applied along [001]cub direction through Vickers micro-indentation. Bright star orthorhombic domains along [110]cub direction and the dark domains of nano-inclusions along [100]cub and [110]cub directions correspond to the creation and annihilation of thin platelet domains for the shuffling model, respectively. Two kinds of dielectric dispersions were found in depoled 24PIN-46PMN-30PT: one is the relaxor type and the other normal one at higher temperatures than the relaxor type.

While macroscopic observation reveals non-switching of domain in Na0.5Bi0.5TiO3 (NBT)-BaTiO3 (Ba;0.33%) rhombohedral (001) plate, microscopic observation, using the piezoresponse force microscopy (PFM), reveals two kinds of piezoresponse images, one with domain switching and the other without one. Such microscopic remarkable difference of domain switching depends on the coercive field caused by localized nucleation of domains with reversed polarization. Such coercive fields was discussed from the viewpoint of the relaxor states resulting from random fields based on lattice defects due to Bi ions and oxygen vacancies.

Electric field-induced switching of nanometer-sized twin related domains were investigated in rhombohedral (R), tetragonal (T) and monoclinic (M) phases in 0.91Pb(Zn1/3Nb2/3)O3–0.09PbTiO3 single crystal by means of scanning force microscopy in piezoresponse mode. Their domain sizes in R, T and M phases were found to be 10–100, ∼200 and 100–300 nm length, respectively. The nucleation and growth in domain switching on the (001)cub surface in R and M phases was found to be prominent in the forward direction rather than in the sideways direction with increasing ac electric field applied along 〈 001 〉 cub direction, providing the enhanced piezoelectric properties on (001)cub surface. On the other hand, in case of (111)cub surface in R phase, electric field-induced domain switching was found to be prominent in the sideways direction, similarly to normal ferroelectric domain switching.

Dielectric properties of the solid solution system (1-x)Pb(Mg 1/3 Nb 2/3 )O 3 −xPbZrO 3 (0 < x < 1) have been studied under hydrostatic pressures up to 0.6 GPa. For the concentration of x ≤ 0.7, the values of the dielectric maximum and the temperature of the dielectric maximum decreased with increasing pressure. For x = 0.9, phase transition from ferroelectric phase to antiferroelectric phase occurs at 0.4 GPa with increasing pressure. For x = 0.95, the dielectric maximum and the peak temperature decreased up to 0.2 GPa, and above 0.2 GPa the peak temperature increased. Pressure-temperature-concentration phase diagram in (1-x)PMN-xPZ was determined by means of dielectric properties and hysteresis loop observation.

The piezoelectric properties of PMN-PT ceramics with compositions near a morphotropic phase boundary were investigated under pressures p upto 150 MPa. The resonance and antiresonance frequency characteristics of impedance and phase in the k 31 mode in the tetragonal phase for PMNT (67/33) and in the rhombohedral one for PMNT (69/31) ceramics were observed under various pressures. The resonance frequency f r remains almost constant and antiresonance one f a tends to increase with increasing p. The electromechanical coupling coefficient k 31 in the k 31 mode increases and the electromechanical quality factor Q decreases with increasing p. The decrease in Q with p is due to ferroelectric domain wall motions. The relative permittivity ϵ r increases with increasing p. Such an increase in both k and ϵ r dependent on p seems to be related to the decrease in ferroelectric domain size.

The piezoelectric and dielectric properties of Pb(Mg1=3Nb2=3)O3–PbTiO3 (PMNT) ceramics with compositions near a morphotropic phase boundary (MPB) were investigated under pressures p up to 700 MPa at 25 � C. The resonance and antiresonance frequency characteristics of impedance and phase in the k31 mode for PMNT (67/33) and (69/31) ceramics were observed under various pressures. The effect of pressure on their responses were clearly observed. The electromechanical coupling coefficient k31 in the k31 mode increases and the electromechanical quality factor Q decreases with increasing p at pressures lower than 100 MPa. The decrease in Q with p is due to the scattering of ultrasonic waves from the domain boundary. The relative permittivity "r increases with increasing p. Such increases in both k and "r with p seem to be related to the increase in topographical domain-wall density associated with monoclinic distortions. At pressures higher than 100 MPa, their electromechanical suppression in PMNT ceramics occurs at each pressure, corresponding to the electromechanical coupling coefficient k. "r increases with pressure-induced electromechanical suppression. The change in "r with such suppression corresponds to k. Such a phenomenon seems to be due to the increase in piezoelectric load based on the increase in complex domain wall density coming from the increase in free energy with pressure. [DOI: 10.1143/JJAP.47.7650]

Synopsis: The in-situ observations of the polarization reversals with the 90° domain wall structures under the low frequency field of 25 mHz were carried out in the c-plate of the ferroelectric Bi 4 Ti 3 O 12 crystal using a polarizing microscope. We found that there exist three kinds of modes in the polarization reversal with respect to the a-domain, that is, changes of the width in a-domains, annihilations of needle like a-domains, and polarization reversals within the a-domain. Computer simulations of the polarization reversal with the 90° domain wall structure were performed on the basis of the Landau theory. Essential parts of the polarization reversal with the a-domain were confirmed to be well reproduced. It was pointed out that the a-domain in the 90° domain wall structure plays an important role in the polarization reversal process.

Piezoelectric properties of Pb[(Mg1/3Nb2/3)0.68]Ti0.32O3 single crystal poled along [001] direction in rhombohedral phase was investigated under pressures(p) up to 700 MPa at 25°. For transverse electromechanical property, the piezoelectric responses on impedance and phase frequency characteristic curves disappeared abruptly above 500 MPa. For longitudinal one, their responses at resonant and antiresonant frequencies become broader above 500 MPa, and piezoelectric response decreased rapidly with p. Such suppression of piezoelectric response above 500 MPa is attributed to decrease in contribution of shear mode due to volume contraction indused by pressures.

The piezoelectric properties of a Pb[(Mg 1/3 Nb 2/3 ) 0.68 ]Ti 0.32 O 3 [PMNT(68/32)]binary system single crystal oriented along the [001] direction in the rhombohedral phase was investigated under pressures up to 400 MPa at 25°C. The electromechanical coupling coefficient k 31 in the k 31 mode decreased markedly with pressure, while the k 33 decreased slightly with pressure. The changes in the elastic compliances s 11 E and s 33 E and mechanical quality factor Q with pressure were estimated. Their properties were discussed in comparison with Pb[(Zn 1/3 Nb 2/3 ) 0.91 ]Ti 0.09 O 3 [PZNT (91/9)].The mechanical hardness with pressure in PZNT(91/9)] is enhanced more than in PMNT(68/32).

The piezoelectric properties of a Pb[(Mg1/3Nb2/3)0.68]Ti0.32O3 [PMNT(68/32)] binary-system single crystal poled along the [001] direction in the rhombohedral phase were investigated under various pressures up to 400 MPa at 25 °C. The electromechanical coupling coefficient k33 in the k33 mode decreased slightly with pressure ( p). k31 decreased markedly with increasing p, and decreased by 16% at 400 MPa. The changes in the elastic compliances s11E and s33E with p were estimated from the changes in resonant frequency [ fr] and antiresonant frequency [ fa] with p. s11E and s33E were 35.4×10-12 and 75.1×10-12 m2/N at 400 MPa, respectively. The slight decrease in the mechanical quality factor Q with increasing p in the k33 mode shows marked contrast to the large decrease in Q in the k31 mode with increasing p up to 200 MPa. The bandwidth of acoustic devices is proportional to the square of k33 and is maintained below 400 MPa. Consequently, the PMNT(68/32) rhombohedral single crystal poled along the [001] direction, offering a k33 of 93% and 10 dB more power under operation at pressures below 400 MPa, is considered to be one of the best candidates from the viewpoint of useful transducer design for ultrasonic devices under water.

The piezoelectric properties of a Pb[(Mg(1/3)Nb(2/3))(0.68)]Ti(0.32)O(3) binary system single crystal poled along the [001] direction in the rhombohedral phase were investigated under pressures up to 400 MPa at 25 °C. For the transverse electromechanical property, the difference Δf between the resonance f(r) and antiresonance frequencies f(a), the Δf/f(r) and the electromechanical coupling coefficient k(31) value in the k(31) mode with hydrostatic pressure (p) became smaller because of the increase in f(r) and the almost constant f(a) with p. The k(31) value decreased by 16% at 400 MPa. On the other hand, for the longitudinal electromechanical property, the Δf, the Δf/f(r) and the k(33) value in the k(33) mode with p remained almost constant because of the almost constant f(r) and f(a) with p. The changes in the values of the elastic compliances s(11)(E) and s(33)(E) with p were found to be large from the changes in f(r) and f(a) with p. s(11)(E) and s(33)(E) at 400 MPa were estimated to be 35.4 and 75.1 × 10(-12) m(2) N(-1), respectively. A mechanical quality factor Q almost constant with p in the k(33) mode in contrast to the large decrease in Q in the k(31) mode with p in the pressure range up to 200 MPa was observed. A k(33) value almost constant with p is considered, on the basis of the engineered domain concept, to be due to the stable domain configuration responsible for the longitudinal k(33) mode. Furthermore, the superior piezoelectric properties of the rhombohedral [001] single crystal in the vicinity of the morphotropic phase boundary composition were recently pointed out to come from the large shear piezoelectric constant d(15) of their single domain property. The hydrostatic pressure cannot influence the piezoelectric properties from the viewpoint of the contribution of the large shear mode d(15), since the uniform pressure introduces no shearing stresses. Consequently, the k(33) value measured for the k(33) mode remained almost constant with p in the measured pressure range.

In this work, in order to investigate the dielectric properties related to the domain structure in PMN-PT solid solutions, simultaneous optical and dielectric measurements were made.

The annealing effect of the phase transition in PbIn½Nb½O3 (PIN) crystal was investigated by means of the dielectric constant measurement and the polarizing microscopic observation. Using one and the same sample plate of the PIN, it was observed that the antiferroelectric transition gradually changes into the diffuse phase transition as the annealing temperature increases. On the basis of the observation by an optical microscope, the annealing effect of the diffuse phase transition in the relaxor was discussed.

In this present study, we have investigated the dielectric behavior of CaCu3Ti4O12, SrCu3Ti4O12 (SCTO), BaCu3Ti4O12 (BCTO), and the pressure and thickness effects of the dielectric property in CCTO.

Domain wall structures on the etched surfaces of the solid solutions of Pb(Zn1/3Nb2/3)O3–xPbTiO3 (PZN-xPT; x≤20%) were investigated by scanning probe microscopy (SPM). We showed that both the 90° and 180° domain wall structures on the etched surface of the PZN-xPT (x=10–20%) can be observed using SPM. We found that complex 180° domain wall structures with a typical size on the 1–2 µm order exist in the c-domain on the (001)-crystal surface of PZN-20%PT. A fingerprint pattern was found on PZN-xPT (x≤8%). It is found that no ferroelastic domain wall structure is observed in the concentration range below x=5%.

Domain observation in Pb(In1/2Nb1/2)O3–PbTiO3[PIN-PT] solid-solution single crystals near the morphotropic phase boundary (MPB) was carried out by polarized light microscopy. The rhombohedral (R)-to-tetragonal (T) phase transition began to take place abruptly in the (110) plane at about 6 kV/cm in the rhombohedral (001) 0.72PIN-0.28PT plate with the dc electric field applied along the direction. The phase boundary between the R and T phases along the (110) plane approached the R region at the expense of the R region, and the R and T phases coexisted in a wide dc field range from 6 kV/cm to 12 kV/cm. The electric-field-induced R-to-T phase transition was very diffuse. The (110) plane plays an important role in this phase transition. The effects of the dc electric field on the domain configuration and permittivity of the rhombohedral (110) 0.69PIN-0.31PT plate were simultaneously investigated, and the contributions of the 109° and 71° polarization configurations to permittivity were discussed on the basis of the Ishibashi theory.

Thermal properties of ordered and disordered Pb(In1/2Nb1/2)O3 (PIN) single crystals were investigated. For the ordered PIN, typical thermal anomalies were observed at the antiferroelectric transition temperature. These anomalies were degraded and disorder appeared during heating processes. The defect-induced phase separation provided a good account of the instability of the relaxor and antiferroelectric states of the PIN crystals.

A single crystal about 15 mm in diameter and 10 mm in length of the lead indium niobate-lead titanate, (1-x)Pb(In1/2Nb1/2)O3–xPbTiO3[PIN–PT(1-x/x)] solid solution system near a morphotropic phase boundary was obtained by the solution Bridgman method using PbO–B2O3 flux. X-ray diffraction study reveals that the ingot cut perpendicularly to the cylindrical as-grown PIN–PT(63/37)(the starting composition) single crystal length exhibits the (110) plane of the perovskite phase, and the wafers cut 2 mm and 10 mm from the bottom of the cylindrical PIN–PT single crystal exhibit the rhombohedral phase and tetragonal one at room temperature, respectively. The crystal growth was almost along the [110] direction. The Ti contents x of these wafers cut at 2 mm and at 10 mm were determined by Inductive Charge Plasma (ICP) chemical analysis to be 0.31 and 0.35, respectively. The Ti content of the as-grown PIN–PT(63/37)(the starting composition) single crystal was found to increase with growth away from the nucleation point. For x=0.31, the relative permittivity er has a peak (37000 at 10 kHz) at the Curie temperature Tc, 300°C and then a shoulder at the ferroelectric rhombohedral to tetragonal phase transition temperature, 120°C with cooling. For x=0.35, the er has a peak (25000 at 10 kHz) at Tc, 313°C.

Domain-wall structures in the vicinity of the morphotropic phase boundary (MPB) in (1-x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 (PZN–xPT) mixed crystals (x=5% and 8%) were investigated by means of a polarizing microscope. It was found that the apparent jump of the indicatrix rotation as a function of temperature appears in the MPB region (x=8%) without the poling process, indicating the occurrence of a phase transition between the tetragonal and rhombohedral phases, despite the fact that this transition is known to be observed only in a poled sample in the case of dielectric constant measurements. We concluded that the sharp phase transition between the tetragonal and rhombohedral phases in the PZN–PT crystal can be observed in the small region of 50 µm order even without the poling process. It was also found that the principal axis of the indicatrix slightly rotates in the MPB region, implying the appearance of the lower symmetry phase such as a monoclinic structure.

Brillouin scattering has been performed on the relaxor ferroelectric Pb(Ni1/3Nb2/3)O3 (PNN) from 80 to 450 K across its Curie temperature. A diffuse phase transition from the paraelectric to ferroelectric phase, associated with a broad phonon frequency dip and a damping maximum, is observed around 200 K. A relaxation mode in the form of a broad Rayleigh wing, whose frequency is strongly temperature dependent above 190 K, is observed and analyzed based on a modified superparaelectric model. Dielectric studies of PNN have also been carried out at several measurement frequencies. The relation between the measurement frequency and the dielectric maximum temperature was analyzed on a modified Vogel–Fulcher model.

Recetvea in final form November 24, 2001) The temperature-concentration dependence of the low frequency modes below 100cm -1 in the solid solution system (1-x) Pb(Zn 1/3 Nb 2/3 )O 3 - xFbTiO 3 (0 ≤ x < 1) was measured by means of the Raman scattering experiment. It was found that the mode softening in the vicinity of the transition point is suppressed with increasing the PZN concentration and no softening of the lowest frequency mode is observed in the pure PZN. The temperature-concentration dependence of the lowest frequency optical mode was discussed.

For lead indium niobate lead titanate(PIN-PT) binary system near the morphotropic phase boundary(MPB) composition with a high Curie Temperature Tc>250 °C, the temperature (30-380 °C), compositions (0.28,0.37,0.38,0.54), and orientation ([100], [111]) dependences of permittivity, dielectric loss tangent, spontaneous polarization, and coercive field were investigated. The poling effect on the permittivity was presented. The electromechanical coupling coefficient in rectangular bar mode, k 33 '=70%, along the [100] axis in the tetragonal 0.62PIN-0.38PT was estimated at 30 °C.

The effect of pressure on the ferroelectric–paraelectric phase transition in the guanidinium compound [C(NH2)3]4Cl2SO4 (G4Cl2SO4) was investigated in the pressure p range up to 500 MPa. Its phase transition temperature Tc decreases with initial pressure coefficient of dTc/dp = −1.2 × 10−1 °C/MPa, in contrast to the positive pressure coefficient of the ferroelastic phase transition temperature in G2PbI4. The relative permittivity ɛr in the paraelectric phase above Tc obeys the Curie–Weiss law under pressures p. The peak value of ɛr at Tc, ɛp decreases remarkably with increasing p. Such decrease of the peak value of ɛp with p results from both the increase in the temperature difference ∆T between Tc and the Curie–Weiss temperature To and the decrease in Curie constant C. The thermal hysteresis in Tc becomes larger (11 and 23 °C at 0 and 300 MPa, respectively) under pressures. The phase transition from ferroelectric II to paraelectric I at Tc becomes sluggish and broad with increasing p. The Tc deviates from the linear relationship to the non-linear one in Tc with p and tends to the change in shape of its curve towards the concave curve, in contrast to the convex one in the KH2PO4 type hydrogen-bonded ferroelectric.

Single crystals and ceramics of (1- x )PMN– x PT were synthesized in the whole concentration range from x =0 to x =1, and the temperature-concentration phase diagram of the system was determined fr...

The largest Pb(In 1/2 Nb 1/2 )O 3 .PbTiO 3 (PIN-PT) binary system single crystal (about 20 mm × 10 mm × 5 mm, 4.5 g) near the morphotropic phase boundary composition with well-developed (100) planes was grown by the flux method using PbO-PbF 2 -B 2 O 3 flux. The PIN-PT(72/28) single crystal was found by simultaneous microdifferential thermal analysis and thermogravimetric analysis to show a peritectic melting at 1283°C with a partial decomposition of the perovskite crystal into a pyrochlore phase, followed by a liquidus point at 1294°C. The electromechanical coupling coefficient in rectangular bar mode, k 33 '=78%, for phased array ultrasonic transducers was obtained by using the rhombohedral PIN-PT(72/28) single crystal oriented along the [001] axis, k 33 '=78% is the highest value reported so far among all the piezoelectric materials with a T c > 250°C and is almost independent of temperature, and even at 200°C decreased only by about 5%. The piezoelectric constant d 33 = 700pC/N Was obtained. The relative permittivity e r decreases after poling. For instance, the e r value of 2650 before poling, decreases to 1500 after poling.

The temperature-concentration dependences of the Raman spectra in the (1−x)Pb(Zn1/3Nb2/3)O3O3-xPbTiO3 mixed crystal system were measured in the high temperature region above the Burns temperature. It was found that in the concentration range below x = 0.8, there are Raman active modes in the cubic phase and intensities of Raman lines decrease with increasing temperature. A finite region where Raman active modes are observed in the cubic phase was determined on the temperature-concentration phase diagram.

The behavior of domain reversal in relaxor Pb(Zn 1/3 Nb 2/3 )O 3 single crystals was studied using X-ray diffraction measurements. After the electric field was switched instantaneously, the {222} B...

PbIn 1/2 Nb 1/2 O 3 (PIN) single crystal plates obtained by different thermal treatment were investigated by means of polarizing microscopic observations. It was found that, in an as-grown PIN (cal...

The Raman spectra of the relaxor ferroelectrics in the single crystals PbMg 1/3 Nb 2/3 O3(PMN), PbMg1/3Ta2/3O 3 (PMT), PbZnl/3Nb2/3O3(PZN) and PbNi1/3Nb2/3O 3 (PNN) have been measured in the frequency range up to 1000 cm −1 and in the temperature range between 100 K and 773 K. It was found that only in the PZN which exhibits the rhombohedral phase in the low temperature range, the spectra in the X(ZZ)Y and X(ZX)Y geometries are almost the same. We found that there are two modes at 50 cm−1 and 790 cm −1 in common in the all samples investigated

The single crystals of Pb(In1/2Nb1/2)O3(PIN)-PbTiO3(PT) solid solution near morphotropic phase boundary(MPB) were flux-grown from PbO-In2O3-Nb2O5-Ti2O3 system using the PbO-B2O3-PbF2 flux. The X-ray studies confirmed that O.67PIN-O.33PT has the rhombohedral structure at room temperature. The temperature, dc-bias field E and pressure p dependences of dielectric properties of PIN-PT single crystals were investigated. The permittivity e has a peak at the Curie point Tc and then a shoulder at the phase transition temperature T1 below Tc with cooling, corresponding to the sequence of transitions of cubic-tetragonal-rhombohedral phases. The value of the spontaneous polarization along the [100] direction in (1-x)PIN-xPT with x=0.33 is about 42 μ C/cm2 at room temperature. The E-T and p-T phase diagrams for (1-x)PIN-xPT single crystals near MPB were determined dielectrically.

The pressure dependence in the disordered Pb(In 1/2 Nb 1/2 )O 3 (PIN) single crystals (S=0.4 (type(I)), 0.2 (type(II))) were investigated by X-ray diffraction. The pressure dependence of the cell p...

The dielectric properties of ferroelectic dimethylammonium gallium sulfate hexahydrate[(CH3)2NH2Ga(SO4)2·6H2O)](DMAGaS) have been investigated under hydrostatic pressures. The paraelectric phase I → ferroelectric phase II transition temperature Tc decreases with dTc/dp = -0.277K/MPa with increasing pressure at pressures below 8.75 MPa(=pt). A remarkable decrease in both the permittivity and the dielectric loss tangent occurred at pt where the ferroelectric phase II disappears. With increasing pressure, the ferroelectric phase II → low temperature phase III transition temperature T1 increases rapidly with the initial pressure coefficient of dT1/dp = 1.95K/MPa, and coincides with Tc at a triple point(pt = 8.75MPa, Tt = -140.3°C), and then the I → III transition temperature increases with a pronounced curvature. The pressure-temperature phase diagram in DMAGaS was dielectrically determined

The phase transition under pressure up to 1 GPa in a relaxor-Pb(In 1/2 Nb 1/2 )O 3 (PIN) single crystal was investigated by X-ray diffraction. With increasing applied pressure, the integrated inten...

Dielectric properties of the disordered and ordered Pb(In 1/2 Nb 1/2 )O 3 (abbreviated as PIN) single crystals were investigated in the range of temperature T from -70 to 200°C and of hydrostatic pressures p up to 0.7 GPa. For the disordered PIN, a typical dielectric dispersion which obeys the empirical Vogel-Fulcher relation was observed. Such dielectric dispersion strength was weakened with an increase in the degree of chemical ordering (S) at the B-site cations in the perovskite ABO 3 , and then relaxor behavior disappears. The relaxor behavior was also weakened with increasing pressure up to 0.7 GPa for the quenched disordered PIN with S=0.2, whereas for the disordered PIN with S=0.4, the relaxor behavior was weakened with increasing pressure and then the antiferroelectric phase transition was induced by the application of pressure above 0.4 GPa. For the ordered PIN, the phase below the transition temperature was confirmed to be antiferroelectric by observation of P - E double hysteresis loops. The st...

The Raman spectra of the relaxor ferroelectrics in the single crystal Pb(Mg1/3Nb2/3)O3 have been measured with the 90° scattering geometry in the wide temperature range between 100 K and 773 K and in the frequency range up to 1000 cm−1. It was found that above the diffuse transtition temperature about 270 K the Raman spectra are reproducible, whereas below 270 K, intensity of the peaks in the Raman spectra in the X(ZX)Y geometry is not reproducible in every run.

Disordered PbIn1/2Nb1/2O3 (PIN) single crystals (S = 0.2) were investigated over the temperature range from −243°C to 300°C by means of X-ray diffraction. The diffuse scattering associated with atomic fluctuation was observed around the (3 0 0), (3 2 0), (3 3 0) and (3 3 3) reflection. The directions of the diffuse scattering were parallel to the [1 1 0] and [1 1 0]. The temperature dependence of the integrated intensity of the diffuse scattering around the (3 2 0) and (3 3 3) was measured. With decreasing temperature, the integrated intensity of the diffuse scattering gradually increased. The temperature dependence of the diffuse scattering intensity in PIN was similar to that in PMN.

We have measured the linear and the third-order nonlinear dielectric constants in (1 – x)Pb (Mg1/2W1/2)O3–xPbTiO3 with concentrations x from 0·075 to 0·6. The third-order nonlinear constant shows a broad maximum in the temperature dependence and the maximum value steeply increases as x is increased. The third-order dielectric constant is positive for all the concentrations measured. The experimental results are discussed on the basis of a few models proposed to explain the linear dielectric properties.

The composition dependence of the structure and dielectric properties of solid solutions Sr2-x Pb x Bi4Ti5O18(0≦ x ≦ 2) (abbreviated as SPBT) was investigated. The unit cell volume of SPBT increases with increasing x. The phase below the transition temperature Tc is confirmed to be ferroelectric by the observation of P–E hysteresis loops. With increasing x, Tc decreases for x 1. Tc increases with increasing pressure. The relaxor behavior appears for x > 1.

The dielectric properties of the deuterated glycinium phosphite crystal were investigated under hydrostatic pressures up to 7 kbar. The paraelectric - ferroelectric phase transition temperature decreases linearly with with increasing hydrostatic pressure p. Pressure effects on its dielectric properties are due to the shift of with pressure. A large isotope effect on the pressure coefficient of the ferroelectric transition temperature as well as on the transition temperature was observed.