Obtaining transparent ferroelectric ceramics requires balancing electrical and optical properties, typically achieved through controlled doping. In this study, densified lead titanate (PT) ceramics doped with different concentrations of lanthanum (PLT18, PLT20, and PLT22) were synthesized and characterized structurally, dielectrically, and optically. All compositions crystallized in a tetragonal perovskite structure; with increasing lanthanum content, the Curie temperature decreased and the diffuseness exponent (γ) increased, indicating a progressively more diffuse transition. Despite these trends, the maximum permittivity remained high and the dielectric loss was generally low. Among the compositions studied, PLT20 defined an optimal window for combined electrical and optical performance: it attained 40

In the search for innovative photovoltaic solutions, bismuth ferrite (BiFeO3) has received significant attention due to the possibility of simultaneous use of its photovoltaic (PV), ferroelectric, and magnetic properties. Furthermore, the possibility of controlling photovoltaic responses through the orientation of ferroelectric and magnetic domains by external fields gives great potential to devices made up of BiFeO3 thin films. This paper investigates PV responses of BiFeO3-based devices under the influence of the different ferroelectric and magnetic domain orientations. We have found a strong correlation polarization/magnetization states with PV. This relation gives rise to a huge increment in photogeneration that goes up to about 7-fold higher than in pristine samples. Thus, BiFeO3-based photovoltaic devices can be highlighted as tunable, multifunctional, and amplifiable systems by electric and magnetic stimuli.

Defect engineering through aliovalent substitution has emerged as an effective strategy for tuning the electrical behavior of functional oxides. Here, aliovalent Ba²⁺ substitution was used to probe defect-mediated charge transport in Bi₅Ti₃FeO₁₅ (BFT4) ceramics. Samples with nominal Ba contents of x = 0.0, 0.5, 1.5, 3.0, and 4.0at.% of the were prepared by solid-state reaction. X-ray diffraction indicated single-phase Ba incorporation up to 3.0at.%. X-ray photoelectron spectroscopy analysis revealed the emergence of mixed-valence states (Fe3+/Fe2+ and Ti4+/Ti3+) at higher Ba contents, attributed to electron trapping at oxygen-vacancy sites generated via aliovalent charge-compensation mechanisms. Within the Mott–Schottky framework, incorporation of Ba2+ was found to decrease the electrostatic potential barrier at the grain boundaries, thereby progressively homogenizing the overall electrical response. Above 1.5at.% Ba, the activation energies approached a plateau, indicating a crossover from grain-boundary-controlled transport to a regime governed primarily by local vacancy migration and transport-pathway connectivity. These results establish Ba substitution as a route to tune the space-charge landscape and electrical homogeneity of BFT4.

This work investigates the incorporation of Cu2+ ions into the crystal lattice of (K,Na)NbO3 single crystals doped with 1 wt% excess CuO (KNN-Cu) grown from the melt by the vertical Bridgman route. By employing the single crystal X-ray diffraction technique, it was found that Cu2+ ions can occupy interstitial sites located between the A- and B-sites in the KNN-Cu single crystals, in contrast to the expected occupations of Cu2+ ions at the A- and Bsites reported in the literature for ceramics produced by solid state method. It is believed that this interstitial occupation of Cu2+ is favored by both the molar excess of CuO and the melting of the precursor oxides. Consequently, the observed variations in lattice parameters, including both contraction and expansion are attributed to the effect of interstitial Cu2+ incorporation.

This study investigates effects of cobalt (Co) substitution and oxygen-vacancy manipulation on the ferrophotovoltaic efficacy of Nd-modified bismuth titanate ceramics, Bi3.25Nd0.75Ti3−xCoxO12 (BNdT-Cox). Cobalt ions were included at the titanium sites to alter the electronic structure and defect chemistry, while oxygen vacancies were systematically adjusted via post-annealing in an oxygen-rich environment for varying durations (0, 4, 8, and 12 h). Rietveld refinement indicated notable octahedral distortions, especially in the Ti(2)O6 octahedra, implying a preferential incorporation of transition-metal ions and the existence of pronounced octahedral tilting and rotation. The structural alterations, along with the creation of oxygen vacancies, decreased the bandgap of pure BNdT from 3.22 eV to 1.88 eV; however, they also diminished the remanent polarization, so constraining the ferrophotovoltaic response. Subsequent oxygen annealing significantly alleviated this trade-off by elevating the bandgap from 1.88 eV to 2.6 eV, concurrently augmenting the remanent polarization from 0.5 to 8 µC/cm² and diminishing the oxygen-vacancy concentration from around 30

A comprehensive study of the ferroelectric domain structure in a [111]c-oriented KNN-Cu single crystal grown by the Bridgman route is presented. The research focused on both visualizing the domain structures in the as-grown crystal and the effects of local poling on them, which is crucial for understanding the microscopic behavior and its correlation with macroscopic piezoelectric properties. The study also reveals the sequential phase transformation from cubic to orthorhombic during cooling, observed optically. The resulting orthorhombic phase exhibits predominantly quasi-periodic lamellar domains with characteristic 60° domain walls and periods of 1–2 μm. By piezoresponse force microscopy, a complex as-grown domain structure consisting of typical herringbone, zigzag, and watermark patterns for KNN-based crystals was identified. Local manipulation with a biased SPM tip demonstrated the domain structure rearrangement and significant reduction in domain sizes. Step-by-step local switching revealed a complex domain structure with charged domain walls, where the created domain size obeys the linear law typical for ferroelectric crystals. The findings contribute to a deeper understanding of the material's microscopic behavior and its relationship with macroscopic piezoelectric properties, filling a gap in the visualization of domain structures in CuO-doped KNN crystals.

Environmental concerns about the effects of the continued use of Pb-based ferroelectric single crystals are encouraging research on alternative lead-free compositions. Among the lead-free materials, (K, Na)NbO3-based ferroelectric single crystals are one of the most promising candidates for the substitution of Pb-based ones. In this work, it was investigated the structural, chemical, and dielectric properties of lead-free Li, Ta, and Sb-modified (K, Na)NbO3 (KNN–LTS) single crystals grown by vertical Bridgman–Stockbarger method. The polycrystalline X-ray diffraction characterization of the crushed KNN–LTS crystals showed a single perovskite phase of the as-grown KNN-LTS boule, thus revealing the success of the growing process. The compositional segregation observed in the crystals was similar to that reported in the literature. The temperature and frequency dependence of the dielectric permittivity were characterized for the [100]c, [001]c, and [111]c crystallographic directions. The results revealed that the domain configuration related to the different measured crystallographic directions played an important role in the dielectric permittivity from room temperature to near the TO–T transition. Higher dielectric permittivity was observed for the [001]c and [100]c directions, due to the contribution of 60° and 90° domain walls. On the other hand, at higher temperatures, it was seen that the compositional variations of Ta5+ content presented a more important influence on the dielectric properties. Similarly, observed in bulk ceramics, it was verified that the higher the Ta5+ amount in the ferroelectric crystals, the lower the dielectric constant near the Curie temperature.

This study describes the fabrication of polycrystalline ceramics Ba1-x(La1/3, Nd1/3)xTiO3 by a solid-state reaction technique. The room temperature X-ray diffraction analysis using Rietveld refinement confirmed the formation of a polycrystalline compound with a tetragonal crystal structure consisting of a single phase. Doping BaTiO3 with La3+ and Nd3+ ions enhanced the relative permittivity at room temperature. The co-doped samples possess a much higher dielectric constant in the wide frequency range, an essential characteristic for producing ceramic capacitors. The P-E hysteresis loop of the investigated samples was performed at room temperature. The results show that the remnant polarisation decreased from 9.05 to 1.95 mu C center dot cm-2 while the breakdown strength increased from 50 kV center dot cm-1 to 167 kV center dot cm-1 when the co-dopants rose from 0 to 8 %. Accordingly, the energy storage density increased from 0.265 to 1.182 J center dot cm-3, and the efficiency also increased from 30 % to 77 %. The BLNT 8 % sample is also very stable throughout a wide temperature range, making it a promising option for future energy storage applications.

One-pot microwave-assisted Pechini synthesis was used to obtain lead-free magnetoelectric composites (1-x)BaZr0.08Ti0.92O3/(x)CoFe2O4 (0.2 <= x <= 0.5) [(1-x)BZT/(x)CFO]. The one-pot microwave-assisted Pechini synthesis was evaluated for the formation of the constituent phases of the composites (BZT and CFO) and the effectiveness of microwave heating compared to conventional heating. It was found that using microwave heating in the one-pot synthesis reduced the solvent evaporation and precursor resin formation duration by up to 59 %, in addition to lowering the crystallization onset temperature of each phase and promoting the complete formation of both constituent phases of the composite in a single thermal treatment at 700 degrees C. The powders of the biphasic composites exhibited ferromagnetic hysteresis even when composed of nanoparticles similar to 10 nm in size. After sintering, the composites achieved high relative densities, reaching up to 99 % for 80BZT/20CFO. Additionally, in the 70BZT/30CFO and 80BZT/20CFO composites, a high dispersion between the constituent phases and homogeneity of the CFO phase was observed, inhibiting percolation. All the (1-x)BZT/(x)CFO (0.2 <= x <= 0.5) composites had an average grain size of less than 1 mu m and exhibited multiferroic properties, with particular attention to the linear magnetoelectric coupling coefficient of 252 mu V/(cm.Oe) corresponding to the nanostructured 80BZT/20CFO composite.

In pursuing enhanced performance for electronic applications, we synthesized ferroelectric materials, specifically Ba(1-x)Nd2x/3TiO3 (BNdTx) nanoceramics, utilizing solid-state reaction techniques coupled with microwave heating treatment. Our investigation involved varying Nd3+-doping levels (x = 0

The Ba0.92(La0.50Li0.50)0.08TiO3 (BLLT0.08) ceramics have been synthesized using both microwave sintering (MWS) and conventional sintering. Our study focused on the synthesized ceramics’ crystal structure, morphology, dielectric, ferroelectric, and energy storage properties. The results indicate that both samples have a tetragonal phase structure. Furthermore, the MWS method improves grain refinement and promotes a more consistent grain size distribution. The MWS approach reduces remnant polarization from 3.36 to 2 kV/cm while increasing breakdown strength from 79 to 104 kV/cm. Bandgap energy widening and small grain size are responsible for the high breakdown strength. The MWS-sintered BLLT0.08 compound has a high energy storage density (Wrec) of 0.81 J/cm3 and an efficiency (η) of 91

This work employs the conventional solid-state reaction method to synthesize Ba0.92La0.08Ti0.95Mg0.05O3 (BLMT5) ceramics. The goal is to investigate how defect dipoles affect the ability of lead-free ferroelectric ceramics made from BaTiO3 to store energy. An extensive examination was performed on the crystal structure, dielectric properties, and energy storage capacity. The analysis found that the polarization hysteresis loops of BLMT5 ceramics had a significant maximum Pm of around 30 µC/cm3 and a low remanent polarization Pr of around 1.80 µC/cm3. In an electric field of 147 kV/cm, defect dipoles significantly increased the recovered energy density, reaching about 1.55 J/cm3. This also increased energy efficiency by over 91

The wide band gap of complex oxides is one of the critical challenges restricting their usage in photovoltaic cells. Therefore, examinations of their photoelectric characteristics have increasingly concentrated on materials with a low band gap. This work investigated the effects of iron doping on samarium-modified Bi4Ti3O12-based oxides (BSmT) made via a solid reaction approach to control the band gap of complex oxides. X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS) were used to study the synthesized materials' structural, optical, and oxygen vacancies. Doping with Fe atoms significantly increased the tunability of the band gap from 3.20 eV to 1.81 eV without violating symmetry. The tuning of bandgap energy in this system was explained based on structural distortion and the formation of oxygen vacancies. This work examined the ferromagnetism and ferroelectricity ordering of the sintered BSmT:F0% and BSmT:F10% samples at room temperature to demonstrate the multiferroelectricity behavior. The findings indicate unsaturated P-E hysteresis loops driven by domain pinning caused by oxygen vacancy formation near domain boundaries. Simultaneously, significant S-type M-H hysteresis loops showed weak ferromagnetic ordering. The findings in this study are encouraging for the development of intrinsic multiferroics for photovoltaic devices for future applications.

This study investigates the effects of Spark Plasma Sintering (SPS) on the physical, structural, microstructural, dielectric, and optical properties of on 87[Pb(1−y)Laₓ(Mg1/3Nb2/3)O3]-13PbTiO3, (PLMN-13PT) ceramics. The primary objective was to evaluate how SPS influences the densification, grain growth, and compositional variations of these ceramics, which are critical for electronic device applications. The results demonstrate that SPS effectively achieves high relative density while suppressing grain growth, leading to a more homogeneous microstructure. However, the rapid densification process also induces compositional variations that significantly impact the dielectric properties, including the reduction of undesirable phases like pyrochlore, which are detrimental to performance. These findings highlight the potential of SPS for optimizing PLMN-13PT ceramics, enhancing their suitability for the miniaturization of multifunctional electronic devices.

The discovery of advanced single-phase multiferroic materials at room temperature is expected to significantly impact the development of a wide range of electronic devices for next-generation applications. Based on this goal, the Co ions were selected as acceptors in the Ti4+ site of the Bi3.25(Sm0.50La0.50)0.75Ti3O12 (BSLT) host lattice. The obtained systems show excellent ferroelectric, magnetic, and magnetodielectric properties. According to the structural analysis, no secondary phase could be observed, and all the prepared samples exhibited layered perovskite structures belonging to the n = 3 Aurivillius family. The morphological study shows that the average grain size decreases with increasing Co content. The ferroelectric and magnetic studies show that the residual polarization and magnetization exhibit opposite variations depending on the doping. The XPS results confirm that the Co is present in a mixed valence state, namely Co2+ and Co3+. This suggests that the ferromagnetism at room temperature could be due to a double exchange interaction between the neighboring Co2+ and Co3+ ions and the oxygen ions. The study of the dielectric constant shows that the real and imaginary dielectric constants have the same trend and increase directly with the magnetic field increase. This indicates that the predominant mechanism of the MD effect is not an extrinsic Maxwell–Wagner mechanism but rather an intrinsic mechanism involving spin realignment of the Co2+–Co3+ dipoles.

Enhancing the efficacy of energy storage materials is crucial for advancing contemporary electronic devices and energy storage technologies. This research focuses on boosting the energy storage capabilities of BaTiO3 ceramics through Mg2+ doping. Introducing Mg2+ ions into the BaTiO3 lattice induces defects and grain boundary effects, significantly influencing ferroelectric properties. Rietveld refinements of X-ray diffraction confirmed that both pure and Mg-doped samples show the same tetragonal phase. SEM analysis revealed a refined grain microstructure in the Mg2+ doped BT sample, which resulted in improved thermal stability and pinched ferroelectric hysteresis loops. Incorporating Mg2+ ions into the BT host lattice significantly enhanced energy storage density from 0.204 J/cm3 to 1.42 J/cm3 and efficiency rising from 21 to 89

This study explores the synthesis and characterization of Fe-doped CaTiO3 compounds via the Pechini method, focusing on their structural, magnetic, and electrical properties. Notably, a previously unreported magnetic property is observed in the Fe-doped CaTiO3 compound. Despite significant structural distortions, ferroelectric polarization is identified using the Geometrical Polarization Approach (GPA), indicating its emergent nature. These distortions are attributed to robust chemical bonds between ionic O1−2 and Ti+4 sites, as evidenced by electronic density maps. This research sheds light on the potential of these materials for various technological applications.

The substitution of fossil energy for green-energy sources is a world demand. Photovoltaic devices are a well-known safety solution to convert solar energy into electricity. Ferroelectric materials are one of the most promising candidates for substituting Si-based compounds in solar-energy conversion devices due to their relatively low cost and bulk photovoltaic effect instead of the classical p-n junction. In this work, (K,Ba)(Nb,Ni)O-3 single crystal was grown by vertical Bridgman-Stockbarger method, and structural, chemical, and optical properties of the as-grown material were characterized. Growth parameters were chosen based on the thermal properties of the precursor oxide and on theoretical models.

This paper proposes a phenomenological description for the nonlinear dielectric permittivity dependence on magnetic field, also called Magnetodielectric (MD) Effect, in strain mediated magnetoelectric composites. The description is derived by incorporating the dielectric dependence on electric polarization, thermodynamic constitutive equations, and magneto-mechanical effects. Moreover, the proposed expression successfully re-produces the experimental behavior reported in existing literature and can provide an explanation for the observed anisotropic effect. Simulations performed using the derived expression demonstrate an inherent cor-relation between the coupling of piezoelectric and magnetostrictive coefficients and the observed MD coefficient curves as measured in experiments. The validity of the model was verified by application to KNN/CFO and KNN/ NFO multiferroic particulate composite samples.