Dielectric relaxation and polar structures of BaTi1−xSnxO3 ceramics, x=0.10–0.20, are investigated by means dielectric spectroscopy piezoresponse force microscopy. A transition regime between “normal” ferroelectric relaxor behaviors is encountered. In the compositions with x=0.10, a complex domain pattern confirming state observed. Strong around Tm attributed to wall motion. On other hand, spectra in sample x=0.20 very similar those observed ferroelectrics. Analysis at intermediate...

Polarized Raman, IR, and time-domain THz spectroscopy of orthorhombic lead zirconate single crystals have yielded a comprehensive picture temperature-dependent quasiharmonic frequencies its low-frequency phonon modes. It is argued that these modes primarily involve vibrations Pb ions librations oxygen octahedra. Their relation to the parent cubic phase proposed. Counts observed IR Raman active belonging distinct irreducible representations agree quite well with group-theory predictions....

A high, rounded peak of the permittivity, ${\mathrm{\ensuremath{\varepsilon}}}_{\mathrm{max}}^{\ensuremath{'}}$\ensuremath{\approx}6\ifmmode\times\else\texttimes\fi{}${10}^{4}$, at T\ensuremath{\approx}18 K evidence a percolative-type phase transition into random-field-induced ferroelectric domain state doped system ${\mathrm{Sr}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Ca}}_{\mathrm{x}}$${\mathrm{TiO}}_{3}$ (x=0.007). Dispersion measurements permittivity reveal strong...

The crystal structure of the perovskite lead zirconate PbZrO 3 has been redetermined using single-crystal X-ray diffraction (Mo K α radiation, λ = 0.71069 Å). Single-crystal data at 100 K: space group. Pbam , a 5.884 (1), b 11.787 (3), c 8.231 (2) Å, V 570.85 Å with Z 8, μ 612.6 cm −1 D x 8.06 Mg m −3 F (000) 1168, final R 0.033, wR 0.061 over 555 reflections I > 2σ( ). An investigation is made into previous contradicting reports possible disorder in O atoms and their origin by examining...

Complex as-grown nanodomain patterns are studied with piezoresponse force microscopy in ${\mathrm{Sr}}_{x}{\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{2}{\mathrm{O}}_{6}$ single crystals at variant $\mathrm{Sr}∕\mathrm{Ba}$ molar ratios, $0.4\ensuremath{\leqslant}x\ensuremath{\leqslant}0.75$. They reflect random-field Ising model (RFIM) ferroelectricity, which crosses over into relaxor behavior increasing $x$. This is explained by an increase of the polar disorder within open...

The highly anisotropic electrocaloric effect, evidenced by both direct measurements and a descriptive theoretical model in lead-free relaxor ferroelectric Sr0.75Ba0.25Nb2O6 single crystals, can be exploited producing low-cost grain-oriented ceramics. Combined with the broad-temperature-range cooling regime provided their polar nanoregions, these materials may key to future cost- energy-efficient solid-state refrigeration.

Owing to their intrinsic charge disorder ferroelectric crystals of strontium-barium-niobate doped with Ce3+ materialize the three-dimensional ferroic random-field Ising model (RFIM) as evidenced by order paramenter and susceptibility criticalities 93Nb NMR dielectric spectroscopy, respectively. Upon cooling towards Tc, extreme critical slowing-down due activated dynamic scaling gives rise relaxor-like dispersion a metastable nanodomain state fractal size distribution imaged piezoelectric...

The full three-dimensional single-crystal crystal structure of the perovskite material PbZrO 3 (M r =346.42) has been refined. It is found that disordered with two substructure components related by a shear c/2. Each individual corresponds closely to tilt system - c 0 Glazer [Acta Cryst. (1972), B28, 33843392; Acta (1975), A31, 756-762]. space group was determined be Pbam (D o 2h ) a=5.889 3), b=11.784 (4) and c=8.226 (2) A, V=570.8 A , Z=8, D x =8.06 Mg m -3 Mo Kα, λ=0.71069 μ=612.68 cm -1 T=297 K

Dielectric relaxation of BaTi1− x Sn O3 ceramics is investigated by means dielectric spectroscopy. The gradual crossover from ferroelectric to relaxor behavior characterized vanishing the contribution due domain walls and appearance related reorientation polar nanosized regions. Typical relaxors observed only in with = 0.30, while compositions 0.175 ≤ 0.25 show coexistence both features. properties are supposed be weak random fields disorder inherent pure BaTiO3.

The electric susceptibilities χ1, χ2, and χ3 of BaTi1−xZrxO3 ceramics with 0.25 ≤ x 0.35 are measured at 90 T 350 K 37 f 106 Hz. Crossover from ferroelectric (x = 0.25) to relaxor behavior 0.35) via coexistence both 0.30) is indicated by increasing polydispersivity suppression χ2 intensity negative tails. properties due weak random fields acting on dipolar Ti4+ clusters in non-polar Zr4+ environment. Frustrated interaction between blocked polar nanoregions yields a cluster glass ground state...

Transmission electron microscopy and neutron diffraction have been used to characterize ceramics single crystals from the rhombohedral region of (x = 0.06-0.45) phase diagram. Electron patterns showed existence superlattice reflections type , where h k l, which are not observed by powder diffraction. The analysis these also revealed satellite spots around associated with periodic antiphase boundaries. origin is explained local regions presenting antiparallel cation displacements, models for...

The charge-disordered three-dimensional uniaxial relaxor ferroelectric ${\mathrm{Sr}}_{0.61}{\mathrm{Ba}}_{0.39}{\mathrm{Nb}}_{2}{\mathrm{O}}_{6}$ splits up into metastable polar nanoregions and paraelectric interfaces upon cooling from above ${T}_{c}$. frozen are verified by piezoresponse force microscopy, respond domainlike to dynamic light scattering dielectric excitation, reveal nonergodicity at $T>{T}_{c}$ via global aging, coalesce nanodomains below Contrastingly, the percolating...

The room-temperature crystal structure of the perovskite lead hafnate PbHfO 3 is investigated using both low-temperature single X-ray diffraction (Mo K α radiation, λ = 0.71069 Å) and polycrystalline neutron (D1A instrument, ILL, 1.90788 Å). Single data at 100 K: space group Pbam , a 5.856 (1), b 11.729 (3), c 8.212 (2) Å, V 564.04 Å with Z 8, μ 97.2 mm −1 F (000) 1424, final R 0.038, wR 0.045 over 439 reflections >1.4σ( ). Polycrystalline 383 5.8582 11.7224 (5), 8.2246 (3) 564.80 χ 2...

Static scaling analysis of the paraelectric susceptibility ${\ensuremath{\chi}}^{\ensuremath{'}}$ ${\mathrm{SrTiO}}_{3}:\mathrm{C}\mathrm{a}$ as a function temperature T and an external electric field E yields very good behavior with consistent values effective exponents \ensuremath{\gamma}, \ensuremath{\delta}, \ensuremath{\Delta}. Further are also calculated. Using quantum scale, it is found that maintained in extreme regime.

Creep and relaxation of domain walls under ac electric fields are observed in an ideal model system, periodically poled ${\mathrm{KTiOPO}}_{4}$, to occur different regimes, which separated by dynamic phase transitions at frequencies ${f}_{m}(T)={f}_{m0}\mathrm{exp}(\ensuremath{-}\ensuremath{\Delta}E/{k}_{B}T)$, with ${f}_{m0}=3\ifmmode\times\else\texttimes\fi{}{10}^{9}\text{ }\text{ }\mathrm{Hz}$ $\ensuremath{\Delta}E=0.6\text{ }\mathrm{eV}$. Power law dispersion the creep susceptibility,...

A fully automatized alternating current (ac) susceptometer is constructed for simultaneous measurements of the phase resolved complex linear and nonlinear ac susceptibilities lossy dispersive dielectric materials. This relatively simple setup allows over a wide range experimental variables, such as amplitudes up to 40 V, frequencies from 10−2 103 Hz, temperatures 100 600 K utilizing only current/voltage analog/digital converters personal computer. In contrast with commonly used analysis...

The crossover of single crystalline Sr x Ba 1 − Nb 2 O 6 (SBN) from ferroelectric to relaxor behavior when increasing the 2+ content = 0.4 0.75 is investigated by dielectric low-frequency susceptometry and scanning piezo-force microscopy. Increasing quenched random electric fields are conjectured be responsible for observed polydispersivity growing fractality polar 180° domains. A simple statistical model taking into account varying occupation different A-sites with vacancies, ions, their...

The electric susceptibilities χ1, χ2, and χ3 of BaTi1−xSnxO3 ceramics with 0.175 ≤ x 0.30 are measured at 90 T 350 K 37 f 106 Hz. Crossover from ferroelectric (x = 0.175) to relaxor behavior 0.30) via coexistence both 0.25) is indicated by increasing polydispersivity suppression χ2 intensity. properties due weak random fields acting on dipolar Ti4+ clusters in non-polar Sn4+ environment. Upon cooling frustrated interaction between the blocked polar nanoregions yields a cluster glass ground...

The electrocaloric effect (ECE) of SrxBa(1−x)Nb2O6 (SBN100x) single crystals, with a tetragonal tungsten bronze structure and high ECE near room temperature, is studied by direct measurements. It shown that although the onset peak closer to temperature in SBN80 than SBN75, increase strontium content very detrimental performances decrease ΔTEC = 0.23 K for from reported value 0.42 under 10 kV/cm SBN75 [F. Le Goupil et al., “Anisotropy lead-free relaxor ferroelectrics,” Adv. Energy Mater....