Type Ferroelectrics Research Articles

Electrophysical properties of multiferroic PMN-PT-Ferrite composites sintered by spark plasma sintering

This study elaborates on the technology of multiferroic ceramic composites sintered by the spark plasma sintering (SPS) method and presents their structural, microstructural, dielectric, ferroelectric and magnetic characteristics. The matrix was the ferroelectric phase, i.e., (1 − x)PMN(x)-PT (PP) material (with x from 0.25 to 0.40), while the magnetic phase was nickel-zinc ferrite (F) in the PP-F composite materials. The X-ray diffraction analysis (XRD) tests revealed that the crystal structure is transformed from the rhombohedral (for x = 0.25) to the tetragonal phase (for x = 0.40) in the PMN-PT component of the composite, and both phases coexist when x = 0.31, 0.34, and 0.37. The energy dispersive spectrometry (EDS) tests confirmed the stoichiometry of the elements in the composite samples, whereas the elemental mapping (for iron and lead) recorded regions of higher saturation for areas with a higher content of the magnetic or ferroelectric phases. The dielectric study of the PP-F composite samples showed high permittivity and small values of the dielectric loss tangent, in the range of 1735–13070 and 0.03–0.32, respectively (at room temperature), while the ferroelectric study showed properly saturated hysteresis loops with high remnant polarization (from 7.62 to 11.47 μC/cm2). The magnetic properties are typical for ferroelectro-ferromagnetic composite materials with slim magnetic hysteresis loops, whereas the change in the ferroelectric phase type does not affect the magnetic properties of the PP-F multiferroic composite. Furthermore, the study showed that the SPS method improves the sinterability of the material while maintaining the high performance parameters of the composite samples and simultaneously considerably lowers the temperature and shortens the processing of the PP-F multiferroic composites.

An Optimized KBe2BO3F2‐Like Structure: The Unity of Deep‐Ultraviolet Transparency, Nonlinear Optical Property, and Ferroelectricity

AbstractAt present, only KBe2BO3F2 (KBBF) can effectively realize a deep‐ultraviolet (DUV) coherent output, while the layered growth habit seriously hinders its application. Here, a new design strategy with an optimized KBBF‐like structure based on the quasi‐phase matching principle is proposed. Thus, the first KBBF‐like ferroelectric, Li2KRb(SO4)2, is designed. It exhibits a short DUV absorption cutoff edge of 163 nm, a large nonlinear optical (NLO) effect of 1.7 × KH2PO4 under a 1064 nm laser, and typical ferroelectricity. More importantly, it completely eliminates the layered structure by replacing K‐F bonds with strong ‐Li‐O‐S‐ ones as the interlayer force. Therefore, this work finds a new promising DUV NLO candidate, a unity of the DUV transparency, NLO response, and ferroelectricity, which is advantageous to explore new DUV NLO materials.

Structure and relaxor ferroelectric behavior of the novel tungsten bronze type ceramic Sr5BiTi3Nb7O30

This paper reports a novel lead-free tungsten bronze type ceramic, Sr5BiTi3Nb7O30, prepared by a conventional high-temperature solid-state reaction route. The crystal structure identified using synchrotron x-ray diffraction data and Raman spectroscopy for Sr5BiTi3Nb7O30 could be described as an average structure with the centrosymmetric space group P4/mbm and a local non-centrosymmetric structure at room temperature. In the second-harmonic generation measurement, the Sr5BiTi3Nb7O30 compound exhibits second-order nonlinear optical behavior, which suggests the material is ferroelectric. Temperature dependence of the dielectric permittivity indicates that the dielectric anomaly in Sr5BiTi3Nb7O30, associated with the disorder on the A and B sites, results in strong frequency dispersion with a low phase-transition temperature. A macroscopic and phenomenological statistical model was employed to describe the temperature dependence of the dielectric responses of Sr5BiTi3Nb7O30 and Sr6Ti2Nb8O30. The calculated sizes of polar nanoregions for both compounds imply structural disorder induced by A and B sites, giving rise to a more diffuse ferroelectric transition for Sr5BiTi3Nb7O30. The smaller polar nanoregions with smaller electrical dipole moments can be activated at lower temperatures, leading to Sr5BiTi3Nb7O30 having a lower Tm (∼260 K) than other tungsten bronze type ferroelectrics. This work charts a promising feasible route to the development of improved relaxor ferroelectrics in tungsten bronze type oxides.

Reduction of depolarization field effect on ferroelectric switching process in semiconductor–relaxor ferroelectric composite

Temperature-dependent dynamic ferroelectric hysteresis of semiconductor–relaxor ferroelectric (0–3) type composite {0.30(ZnO)–0.70[(Bi0.5Na0.5)0.94Ba0.06TiO3 (BNBTO)]} has been investigated using polarization–electric field (P–E) loops, current density–electric field (J–E) curves, and temperature-dependent dielectric permittivity. It is well known that the polarization reversal mechanism can be explained by the concept of ferroelectric domain switching kinetics, which depends strongly on the temperature. The present work ascribes the role of polar nanoregion induced thermal depolarization field on the temperature-dependent ferroelectric hysteresis loop along with polarization reversal mechanism. The present composite exhibits unique ferroelectric switching behavior above the thermal depolarization temperature (∼100 °C), which is observed in P–E and J–E loops. The depolarization field-induced pinched P–E loops of a BNBTO solid solution above Td (∼100 °C) have been significantly overcome by the incorporation of semiconductor (ZnO) particles, which extensively described the underlying mechanism in the present context. In addition, the temperature-dependent polarization reversal mechanism displays unique two-stage processes [low-T (<100 °C) and high-T (>100 °C)] for the minor loops (∼30 and 40 kV) and saturated loops (∼45 kV) as described by the electric field–temperature phase diagram. The present results may provide a distinct way to Bi0.5Na0.5TiO3-based solid solutions for high-temperature piezoelectric applications.

Interfacial triferroicity in monolayer chromium dihalide

Couplings between different ferroics in two-dimensional (2D) materials, with atomic thickness and van der Waals surface, have been long sought but not yet realized. Here we show the first-principles evidence of unique triferroic couplings in recently synthesized ${\mathrm{CrI}}_{2}$ monolayer. Its ferroelasticity with a low switching barrier stems from the Jahn-Teller effect. When coupled with the interaction of a substrate, a type of interfacial ferroelectricity with direction determined by the ferroelastic states can emerge which can be switched following the same low-barrier pathway of ferroelastic switching. The direction of its striped antiferromagnetism is also governed by its ferroelastic states, leading to a coupling of ferroelasticity, ferroelectricity, and magnetism. Such mechanism of multiferroic couplings, denoted as interfacial Jahn-Teller triferroicity, can be applied to other 2D materials such as ${\mathrm{CuCl}}_{2}$ and their Janus monolayers, enabling electrical manipulation of spintronics for efficient nonvolatile random-access memories.

Phosphogermanate Crystal: A New Ultraviolet-Infrared Nonlinear Optical Crystal with Excellent Optical Performances.

The phase matching ability is a key factor for nonlinear optical crystals to realize coherent output. Herein, a new design strategy combining ultraviolet and infrared functional groups into a ferroelectric was put forward. Thus, a phosphogermanate crystal, KGeOPO4, was designed and studied. It exhibits a wide transparency window (0.22-9.70 μm), a strong second harmonic generation response (5× KH2PO4), a high laser-induced damage threshold (1.61 GW/cm2), and the typical ferroelectricity (coercive field ∼ 9.8 kV/cm and remnant polarization ∼7.6 μC/cm2). In the infrared region, it could realize coherent output by the birefringence phase matching method, while it could generate ultraviolet coherent lights by the quasi-phase matching technique. Therefore, this work designs a promising ultraviolet-infrared nonlinear optical crystal and provides a new perspective for exploring nonlinear optical crystals.

Understanding electrocaloric cooling of ferroelectrics guided by phase‐field modeling

AbstractWith the urgent need to explore low‐cost, high‐efficiency solid‐state refrigeration technology, the electrocaloric effects of ferroelectric materials have attracted much attention in the past decades. With the development of modern computing technology, the phase‐field method is widely used to simulate the evolution of microstructure at mesoscale and predict the properties of different types of ferroelectric materials. In this article, we review the recent progress of electrocaloric effects from phenomenological Landau thermodynamics theory to phase‐field simulation by discussing the microcosmic composition, mesoscopic domain structures, macroscopic size/shape, and external stimulus of strain/stress. More importantly, in searching for new ferroelectric electrocaloric cooling materials, it is possible to find materials whose free energy barrier height changes rapidly with temperature, such materials have a faster change rate with polarization temperature in terms of ferroelectric macroscopic properties, from them could get superior electrocaloric effects. We compile a relatively comprehensive computational design on the high performance of electrocaloric effects in different types of ferroelectrics and offer a perspective on the computational design of electrocaloric refrigeration materials at the mesoscale microstructure level.

Room-Temperature Ferroelectricity in 1T^{'}-ReS_{2} Multilayers.

van der Waals materials possess an innate layer degree of freedom and thus are excellent candidates for exploring emergent two-dimensional ferroelectricity induced by interlayer translation. However, despite being theoretically predicted, experimental realization of this type of ferroelectricity is scarce at the current stage. Here, we demonstrate robust sliding ferroelectricity in semiconducting 1T^{'}-ReS_{2} multilayers via a combined study of theory and experiment. Room-temperature vertical ferroelectricity is observed in two-dimensional 1T^{'}-ReS_{2} with layer number N≥2. The electric polarization stems from the uncompensated charge transfer between layers and can be switched by interlayer sliding. For bilayer 1T^{'}-ReS_{2}, the ferroelectric transition temperature is estimated to be ∼405 K from the second harmonic generation measurements. Our results highlight the importance of interlayer engineering in the realization of atomic-scale ferroelectricity.

SbCl4: An Exceptional Superhalogen as the Building Block of a Mixed Valence Supercrystal with Unconventional Ferroelectricity.

Superhalogens are nanoclusters with high electron affinities, exhibiting behavior similar to that of halogens. Their dimerization yields nonpolar symmetrical clusters, akin to diatomic halogen molecules, and they are unstable in the condensed phase in the absence of charge-compensating cations. Herein, we provide ab initio evidence that SbCl4 superhalogen is an exception: its dimerization yields a polar cluster that can be viewed as a quasi-bonded [SbCl5]δ- and [SbCl3]δ+ Lewis acid-base cluster. The symmetry breaking arises from the valence stratification of Sb into Sb5+ and Sb3+ as well as their lone pair electrons. When assembled, SbCl4 clusters form a supercrystal that is thermodynamically stable up to 600 K, with the unique bonding feature of Sb2Cl8 prevailing in the bulk phase. Combination of mixed valence and lone pair electrons leads to electric polarizations along all directions, generating a type of unconventional multimode ferroelectricity in which three different modes of ferroelectricity with distinct magnitudes and Curie temperature are revealed.

Molecular dynamics simulation of typical molecular ferroelectrics based on polarized crystal charge model

Molecular ferroelectrics are a promising class of ferro-electrics, with environmental friendliness, flexibility and low cost. In this work, a set of characteristic molecular ferroelectrics are simulated by molecular dynamics (MD) with polarized crystal charge (PCC). From the simulated results, their ferroelectric switching mechanisms are elucidated, with their ferroelectric hysteresis loops. The PCC charge model, recently developed by our group, containing the quantum electric polarization effect, is suitable in nature for studying molecular ferroelectrics. The simulated systems include the typical molecular ionic ferroelectrics, di-isopropyl-ammonium halide (DIPAX, X=C (Cl), B (Br), and I), as well as a pair of newly validated organic molecular ferroelectrics, salicylideneaniline and (-)-camphanic acid. In total, there are five systems under investigation. Results demonstrate that the PCC MD method is efficient and reliable. It not only elucidates the ferroelectric switching mechanism of the studied molecular ferroelectrics, but also extends the application range of the PCC MD. In conclusion, PCC MD provides an efficient protocol for extensive computer simulations of molecular ferroelectrics, with reliable ferroelectric properties and associated mechanisms, and would promote further exploration of novel molecular ferroelectrics.

Large electrostrictive coefficients of BaTiO<sub>3</sub>-based lead-free ceramics

AbstractMicro-displacement actuators have important applications in aerospace, semiconductor, industry and other fields. Now most of the lead-based piezoelectric ceramics are used in the market. In consideration of environmental protection and legal restriction, it is urgent to develop lead-free ceramic materials with excellent electrostrictive properties. As a kind of ABO<sub>3</sub>-type ferroelectrics, (Ba,Ca)(Ti,Zr)O<sub>3</sub> lead-free ceramics have attracted a lot of attention because of their high piezoelectricity. In this work, (Ba<sub>0.85</sub>Ca<sub>0.15</sub>)(Ti<sub>0.9</sub>Zr<sub>0.1</sub>)O<sub>3</sub> (BCTZ) ceramics with high electrostrictive coefficient are prepared by the solid-state method. The effects of sintering temperature on the structures and electrical properties of BCTZ ceramics are studied. The results show that the sintering temperature can help to improve density and grain growth of BCTZ ceramic.There are no impurity phases in the BCTZ ceramic systems, and all samples show ABO<sub>3</sub>-type perovskite structures. At room temperature, the crystal structure of BCTZ ceramic forms coexistence of orthogonal (O)-tetragonal (T) phase. The dielectric peak of BCTZ ceramic is widened, and the Curie temperature reaches a maximum value of 110 ℃ when <i>T</i><sub>s</sub> = 1300 ℃. With the increase of sintering temperature, the dielectric peak of BCTZ ceramic gradually becomes narrowed, and the Curie temperature of ceramic moves toward low temperature.As the sintering temperature is 1300 ℃, the grain size of BCTZ ceramic is 1 μm, the large electrostrictive coefficient <i>Q</i><sub>33</sub> (5.84 × 10<sup>–2</sup> m<sup>4</sup>/C<sup>2</sup>) can be obtained, which is about twice that of traditional PZT ceramic. This may be attributed to combination of the surface effect caused by grain size of BCTZ ceramic with the strong ionic nature of A-O chemical bond. In addition, although BCTZ ceramic has an O-T phase boundary near room temperature, the electrostrictive coefficient <i>Q</i><sub>33</sub> of ceramic has good temperature stability in a range of 25–100 ℃. It shows that the crystal phase and temperature have no effect on the electrostrictive coefficient of BCTZ lead-free ceramic. It provides a new idea for designing the high electrostrictive properties of lead-free piezoelectric ceramics with potential applications.

Ferroelectric Materials for Solar Energy Scavenging and Photodetectors

AbstractThe photovoltaic devices based on ferroelectrics have drawn plenty of attention for providing a promising solar energy harvesting technology and efficient photodetectors. In this review, mainly the photoelectric properties of ferroelectric materials are introduced. First, three different types of ferroelectrics and primary representative materials are reviewed. Second, four existing principles and mechanisms of the photovoltaic effect in ferroelectrics are studied in great detail. Then, the typical design construction utilizing ferroelectrics for solar energy scavenging, photodetectors, and other photovoltaic device architectures is summarized. Lastly, the properties and characteristics of photovoltaic devices based on ferroelectrics are reviewed in the form of tables and the prospect of ferroelectric photovoltaic devices is discussed.

Optically Induced Ferroelectric Polarization Switching in a Molecular Ferroelectric with Reversible Photoisomerization.

Ferroelectrics usually exhibit temperature‐triggered structural changes, which play crucial roles in controlling their physical properties. However, although light is very striking as a non‐contact, non‐destructive, and remotely controlled external stimuli, ferroelectric crystals with light‐triggered structural changes are very rare, which holds promise for optical control of ferroelectric properties. Here, an organic molecular ferroelectric, N‐salicylidene‐2,3,4,5,6‐pentafluoroaniline (SA‐PFA), which shows light‐triggered structural change of reversible photoisomerization between cis‐enol and trans‐keto configuration is reported. SA‐PFA presents clear ferroelectricity with the saturate polarization of 0.84 μC cm−2, larger than those of some typical organic ferroelectrics with thermodynamically structural changes. Benefit from the reversible photoisomerization, the dielectric real part of SA‐PFA can be reversibly switched by light. More strikingly, the photoisomerization enables SA‐PFA to show reversible optically induced ferroelectric polarization switching. Such intriguing behaviors make SPFA a potential candidate for application in next‐generation photo‐controlled ferroelectric devices. This work sheds light on further exploration of more excellent molecular ferroelectrics with light‐triggered structural changes for optical control of ferroelectric properties.

Theoretical investigation, of Cochran’s mode frequency, and electrical permittivity of KH2AsO4 (KDA) crystal by using Zuberav’s statistical Green function technique

Potassium dihydrogen arsenate KH2AsO4 crystal is investigated theoretically. It is an order disorder type of ferroelectrics. Another type is displacive like SrTiO3, LiNbO3, etc. The earlier model Hamiltonian (PLCM) is modified by adding some extra terms into it. Applying two time thermal dependent statistical Green function technique employing modified model, formulae for, Cochran’s mode frequency, electrical permittivity, Curie temperature, tangent delta, shift and width, are derived for the potassium dihydrogen arsenate crystal. Model values are fitted for KH2AsO4 crystal to obtain variation with temperature. Results are compared with experimental variations shown by Kaminow et al. [4] for the alkali phosphate potassium dihydrogen arsenate KH2AsO4 crystal.

An Order–Disorder Type High‐Temperature Multiaxial Supramolecular Ferroelectric

AbstractMuch progress has been witnessed in exploring host–guest type ferroelectrics represented by ammonium‐crown ether compounds. However, the major obstacles in expanding their promising applications in nonvolatile memory elements, capacitors, and sensors are relatively low Curie temperature (Tc) and uniaxial attribute. Herein, by screening different organic cations and inorganic anions to assemble with 18‐crown‐6 molecule, it is found that a new ammonium‐crown ether inclusion ferroelectric 1, [(ATHTP)(18‐crown‐6)]BF4 (ATHTP = protonated 4‐aminotetrahydrothiopyran), undergoing a ferroelectric phase transition at a much higher Tc of 392 K which is comparable to BaTiO3 (Tc = 393 K). Notably, the distinct symmetry breaking, that is, 4/mmmFmm2, leads to a biaxial ferroelectric with four equivalent directions of polarization. Such high Tc and multiaxial nature are rare in existing crown ether‐based ferroelectrics. This work can help the exploration of high‐Tc multiaxial ferroelectrics toward further device applications.

Coherence in the Ferroelectric A3ClO (A = Li, Na) Family of Electrolytes.

Coherence is a major caveat in quantum computing. While phonons and electrons are weakly coupled in a glass, topological insulators strongly depend on the electron-phonon coupling. Knowledge of the electron−phonon interaction at conducting surfaces is relevant from a fundamental point of view as well as for various applications, such as two-dimensional and quasi-1D superconductivity in nanotechnology. Similarly, the electron−phonon interaction plays a relevant role in other transport properties e.g., thermoelectricity, low-dimensional systems as layered Bi and Sb chalcogenides, and quasi-crystalline materials. Glass-electrolyte ferroelectric energy storage cells exhibit self-charge and self-cycling related to topological superconductivity and electron-phonon coupling; phonon coherence is therefore important. By recurring to ab initio molecular dynamics, it was demonstrated the tendency of the Li3ClO, Li2.92Ba0.04ClO, Na3ClO, and Na2.92Ba0.04ClO ferroelectric-electrolytes to keep phonon oscillation coherence for a short lapse of time in ps. Double-well energy potentials were obtained while the electrolyte systems were thermostatted in a heat bath at a constant temperature. The latter occurrences indicate ferroelectric type behavior but do not justify the coherent self-oscillations observed in all types of cells containing these families of electrolytes and, therefore, an emergent type phenomenon where the full cell works as a feedback system allowing oscillations coherence must be realized. A comparison with amorphous SiO2 was performed and the specific heats for the various species were calculated.

Investigation on diffuse phase transition through Raman and dielectric properties of Pb(Fe0.5Nb0.5)O3 – Pb(Co0.33Nb0.67)O3 solid solutions

We report a series of Pb based multiferroic solid solutions (1-x) Pb(Fe0.5Nb0.5)O3 – (x) Pb(Co0.33Nb0.67)O3 (0.1 ≤ x ≤ 0.5) (shortened as PFCN), synthesized using a single-step solid-state reaction method. The structural, microstructural, Raman, and temperature (301–481 K) dependent dielectric (102–106 Hz) and conductivity properties were thoroughly investigated. The room temperature X-ray diffraction data reveals the monoclinic phase with the Cm space group for all the solid solutions. The atomic-level structural parameters were obtained for all the solid solutions from the Rietveld refinement technique, and it was observed that an increase in the unit cell volume with an increase of PCN content in PFN. The field emission scanning electron microscope images confirm the densely packed, uniform coarse arrangement in all the samples. In x = 0.4 and 0.5, a small amount of porous structure was noticed, indicates the reduction in the densities. Energy-dispersive X-ray spectroscopy reveals the existence of Pb, Fe, Co, Nb, and O elements according to stoichiometry. The temperature-dependent Raman spectra of all the solid solutions show a decrease in the intensity and changes in the spectral line shape of B-localized F1u (~250 cm−1) and BO6 octahedral rotation F1g (~260 cm−1) modes around the characteristic temperature, may be a structural transformation from monoclinic to cubic above Tm. The frequency-dependent ε′ and tanδ reveal the presence of Maxwell-Wagner polarization in the lower frequency. The temperature-dependent ε′ shows the ferroelectric relaxor type diffused phase transition Tm (TC) around ~360 K, ~340 K, ~330 K & ~320 K for x = 0.1, 0.2, 0.3 and 0.4, respectively. The reported Tm (TC) systematically decreases with increasing x due to the lower Tm (TC) of PCN compared to PFN. These results were consistent with the anomalies observed at the vicinity of Tm in the Raman spectra. The frequency-dependent ac-conductivity studies reveal the negative temperature coefficient of resistance behavior and obey Johnscher's power law. For x = 0.1 to 0.4, the hump-like behavior was found in both temperature-dependent tanδ and ac conductivity around the transition temperature related to the reorientation of domains, domain wall motion, dipolar contribution to the ferroelectric materials.

Enhanced Energy-Storage Density by Reversible Domain Switching in Acceptor-Doped Ferroelectrics

Typical ferroelectrics possess a large spontaneous polarization Ps but simultaneously a large remnant polarization Pr as well, resulting in an inferior energy storage density.A mechanism that can reduce the Pr while maintain the Ps is demanded to enhance the energy storage property of ferroelectrics.In the present study, it is shown that after acceptor doping and aging treatment, the domain switching in ferroelectrics becomes reversible, giving rise to a pinched double hysteresis loop. The pinched loop with a large Ps and a small Pr thus results in an enhanced energy storage density. The physics behind is a defect induced internal field that provides a restoring force for the domains to switch back.The idea is demonstrated through a time-dependent Ginzburg-Landau simulation as well as experimental measurements in BaTiO$_3$ based single crystal and ceramics. The mechanism is general and can be applied to various ferroelectrics, especially the environment-friendly ones.

Compensating for artifacts in scanning near-field optical microscopy due to electrostatics

Nanotechnology and modern materials science demand reliable local probing techniques on the nanoscopic length scale. Most commonly, scanning probe microscopy methods are applied in numerous variants and shades, for probing the different sample properties. Scattering scanning near-field optical microscopy (s-SNOM), in particular, is sensitive to the local optical response of a sample, by scattering light off an atomic force microscopy (AFM) tip, yielding a wavelength-independent lateral resolution in the order of ∼10 nm. However, local electric potential variations on the sample surface may severely affect the probe–sample interaction, thereby introducing artifacts into both the optical near-field signal and the AFM topography. On the other hand, Kelvin-probe force microscopy (KPFM) is capable of both probing and compensating such local electric potentials by applying a combination of ac and dc-voltages to the AFM tip. Here, we propose to combine s-SNOM with KPFM in order to compensate for undesirable electrostatic interaction, enabling the in situ probing of local electric potentials along with pristine optical responses and topography of sample surfaces. We demonstrate the suitability of this method for different types of materials, namely, metals (Au), semiconductors (Si), dielectrics (SiO2), and ferroelectrics (BaTiO3), by exploring the influence of charges in the systems as well as the capability of KPFM to compensate for the resulting electric force interactions.

Effects of Gd-substitution on structural, and impedance spectroscopic study of Sr2Sm1−xGdxTi2Nb3O15 tungsten bronze ceramics

In the present work, we have studied the effect of Gd-substitution on the structural, dielectric and electrical properties of Sr2Sm1−xGdxTi2Nb3O15 (x = 0 and 0.5) tungsten bronze ceramics prepared by a high-temperature solid-state reaction technique. The formation of the phase of tetragonal tungsten bronze was verified by the Rietveld refinement using X-ray diffraction data. With increasing Gd concentration, the crystal structure of the Sr2Sm1−xGdxTi2Nb3O15 ceramics has slightly deformed from the tetragonal P4bm phase to the paraelectric P4/mbm phase. Scanning electron microscopy (SEM) of ceramics shows high densification and homogeneous distribution of grains of different sizes over the total surface. The crystallite size increases with Gd-substitution from 6.19 nm for Sr2SmTi2Nb3O15 to 10.83 nm for Sr2Sm0.5Gd0.5Ti2Nb3O15. The sample Sr2SmTi2Nb3O15 shows a dielectric anomaly of ferroelectric paraelectric type at 332 °C, and has non-relaxor type of diffuse phase transition. In addition, the dielectric properties deteriorated and even disappeared for the sample Sr2Sm0.5Gd0.5Ti2Nb3O15, because the ceramic presented a P4/mbm phase structure as a result of the decrease in Curie temperature (Tc) below room temperature. The electrical property of Sr2Sm1−xGdxTi2Nb3O15 ceramic has been investigated by non-destructive complex impedance spectroscopy (CIS) as a function of frequency at different temperatures.