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In this study, we provide the synthesis and analysis of the structure, microstructure, and spectroscopic properties of V‐doped SrTiO3. The monophasic samples were made using the usual ceramic method, which involved calcination at temperatures of 1000°C and 1300°C. The X‐ray diffraction analysis, combined with the Rietveld refinement, conclusively demonstrates that they have crystallized in a cubic structure, namely under the space group Pm3¯m$Pm\bar{3}m$. The inclusion of vanadium (V) at the titanium (Ti) site has been investigated by evaluating the size of the crystallite and grain. The investigation of dielectric and dissipation factors at different frequencies indicates the existence of interfacial and orientational polarization. Two distinct conduction and relaxation processes were identified within the temperature range examined based on the spectroscopic plot. The presence of a paramagnetic phase in the samples, caused by the presence of V and its magnetic interaction with oxygen vacancies, indicates that it can be classified as a soft magnetic material. The electrode's consistent dielectric constant and dissipation factor make it well‐suited for use in supercapacitor dielectric capacitors. Additionally, its mixed‐type conduction, involving both ionic and electronic conduction, makes it excellent for use as electrode materials in intermediate‐temperature solid oxide fuel cells' applications. [ABSTRACT FROM AUTHOR]

The samples with A‐site cation ordering Ba1−x/2Ti1−xNbxO3 (BTN) with 0 ≤ x ≤ 0.010 were synthesized via the conventional ceramic route by calcining at 1200°C and sintered at 1350°C. The preliminary study of the phase of prepared samples was determined through X‐ray diffraction (XRD) analysis. The Rietveld refinement analysis indicates the tetragonal phase in BTN0 sample, whereas the doped samples exhibit a combination of tetragonal and cubic phases. Presence of Raman band at 308 cm−1 suggests the presence of tetragonal in all samples. The dielectric constant was observed to be 1500 (BTN0), 3000 (BTN5) and 1680 (BTN10) while tangent loss found 0.6 (BTN0), 0.04 (BTN5) and 0.07 (BTN10). All the sample shows same Curie temperature (120°C) due to Ba‐site cation ordering in the sample. Ferroelectric nature in all samples was also confirmed by modified Curie‐Weis law. Based on the current studies, the present materials can be explored as a potential candidate for ferroelectric‐memory devices, dielectric capacitor and energy harvesting applications. [ABSTRACT FROM AUTHOR]

This article reports domain size-controlled magnetic behavior of La0.67Ca0.33MnO3 perovskite which was prepared by solid state reaction. The detail study includes structural information obtained with the help of Rietveld refinement of X-ray diffraction analysis. The structure was found as orthorhombic with the lattice parameters: a = 5.4850(4) Å, b = 5.4853(7) Å, c = 7.7583(9) Å belonging to the space group Pbnm . In addition, the crystallite size and micro-strain in the sample was found of the order of ~ 34 nm and 5.92 × 10−3, respectively. The surface morphological study was also carried out with the help of FESEM with the EDAX analysis for verification of elemental composition which shows that the wt% of La, Ca, Mn and O elements were found as ~ 46.2, 3.8, 25.9 and 24.1, respectively, which is approximately equal to experimental values obtained by EDAX measurements. The SQUID was used to measure magnetic properties. The M–T measurements show that the reduction of departure between ZFC and FC curves with increasing magnetic field (B) is due to the overcome of external magnetic field to internal magnetic field of the sample. The M–H measurements were recorded showing the variation of magnetization as a function of B field at different temperatures (T = 5 K, 50 K, 100 K, 120 K, 200 K, and 300 K) within ± 5 T. The absence of saturation at 300 K supports paramagnetic nature. The ΔM/ΔH under B field and variable T were also determined to study the domain size. The study of inverse susceptibility with temperature shows a straight line characteristic of the Curie–Weiss law with finding of Curie temperature as 212 K. Further dM/dT in FC mode shows a sharp peak at temperature 183 K which suggests that at this temperature thermal energy destroy the magnetic domain energy and magnetic moment aligns in random directions due to thermal energy. [ABSTRACT FROM AUTHOR]

Samples of the system SrCe1−xGdxO3 (x = 0.0, 0.02, 0.04, 0.06 and 0.10) were prepared using a conventional ceramic route. The phase and structural properties of samples were investigated using X-ray diffraction. Rietveld refinement of the XRD data supported the crystallization of samples in an orthorhombic structure under space group Pnma . FTIR and TGA measurements indicated the presence of SrCO3 in all the samples. The incorporation of Gd into the lattice was shown to reduce the direct optical bandgap and average grain size. The DC conductivity of the cylindrical pellets of samples was investigated using AC impedance measurements at temperatures ranging from 300 to 600 °C. The highest conductivity was observed for the composition SrCe0.98Gd0.02O3 such as 1.54 × 10−3 Scm−1 at 600 °C. This compound has the potential to be work as mixed ionic and electronic conductor for SOFCs. The XPS spectra of Ce 3d and O 1 s confirmed the presence of Ce in both Ce3+ and Ce4+ states and oxygen vacancies. The oxygen vacancies in the samples were analyzed using Raman spectroscopy. [ABSTRACT FROM AUTHOR]

(1 − x)BiFeO3–(x)CaTiO3 [(1 − x)BFO–(x)CTO, (x = 0, 0.1, 0.2 and 0.3)] composites were synthesized using sol–gel chemical method. Rietveld refinement was performed on X-ray diffraction data of all the samples reflect rhombohedral structure for x = 0, 0.1, 0.2 and the mixture of rhombohedral and orthorhombic structure for x = 0.3. The Field Emission Scanning Electron Microscope (FESEM) investigation confirms the microstructure consists of randomly oriented, homogenous, and non-uniform grains. The dielectric permittivity (ε) and tangent loss (tan δ) decreases with increasing frequency and show dielectric anomalies (as a hump) at different temperatures for different compositions. The incorporation of CTO decreases three order of leakage current (up to x = 0.2) and significantly improve the magnetization and magneto-dielectric coupling. The frequency-dependent ac conductivity obeys Jonscher's power law with large ac conductivity dispersion for higher frequencies with increasing CTO concentration. The variations of ac conductivity with the inverse of temperature obey the Arrhenius equation and show negative temperature coefficient of resistance (NTCR) behaviour. The ferromagnetic (FM) properties in BFO–CTO increases significantly with the increase of CTO concentration. The coercive field increases with increasing CTO concentration suggesting a competition between the antiferromagnetic and ferromagnetic ordering. The BFO–CTO samples exhibit large positive and negative magneto-dielectric coupling effect at room temperature. [ABSTRACT FROM AUTHOR]

Powders of a few compositions of the system Sr2Ce1-xNaxO4 (x = 0, 0.02, 0.04, 0.06, and 0.10) have been prepared by the conventional solid-state reaction method. Analysis of the XRD patterns has shown a preference of dopant Na+ for the Sr2+ sites with increasing content of dopant (x). Rietveld refinement of the XRD patterns confirmed that each sample crystallized in orthorhombic structure with space group Pbam. The purity of the synthesized samples was further examined using Raman Fourier Transform Infrared (FTIR) spectroscopy techniques. Raman spectroscopy has further indicated the risk of decomposition of Sr2CeO4 phase with increasing doping concentration. Optical band gap energy computed using UV–visible absorption data (Tauc's plot) falls between 2.91 and 3.10 eV, decreasing with increasing x. The shape of the excitation and emission spectra remains unchanged with increasing Na+ concentration. Two excitation peaks located around 290 nm and 350 nm are seen in photoluminescence (PL) excitation spectra. All Na-doped samples display an intense blue emission at 472 nm similar to undoped Sr2CeO4. SEM images of fractured surfaces of the sintered pellets have shown a significant role of Na doping on the morphology and grain size of the Sr2CeO4. [ABSTRACT FROM AUTHOR]

The samples SrSnO3 (SBS0) and Sr0.98Ba0.02SnO3 (SBS2) were synthesized using sol–gel route, followed by calcination at 1073 K. Rietveld refinement analysis of XRD data shows orthorhombic phase under Pbnm space group. Lattice parameters, volume and density of the doped sample were found to be higher than undoped, due to higher ionic radii of Ba2+. Further, the Raman spectrum of samples was carried out to study the local structure. Optical properties of samples show intense absorption in UV range and transparent in visible to NIR region. The direct bandgap of samples was found to be 3.88 eV and 3.97 eV for SBS0 and SBS2, respectively, reflecting the semiconducting nature of a sample. Dielectric properties of the sample were explained in terms of interfacial and orientational polarization. Temperature-dependent conductivity analysis of the sample reflected an Arrhenius-type charge transport, with two conduction regions in SBS2 and single conduction in SBS0. In the present case, the activation energy value represents a mixed ionic and electronic conductivity of the sample, making it a promising candidate for mixed ionic and electronic conductor device application. [ABSTRACT FROM AUTHOR]

The samples of Sr2‐xNdxSnO4 with x = 0, 0.01, 0.02, 0.04, 0.06, and 0.10 were synthesized by a high‐temperature solid‐state ceramic route. Rietveld refining of X‐ray diffraction results showed that all the synthesized compositions are single phase under tetragonal crystal structure. The presence of functional group and local structure has been studied using FTIR and Raman spectroscopy, respectively. XPS study of samples showed the presence of oxygen vacancy and interstitial oxygen in the sample. Optical band gap of samples analyzed by UV‐Vis spectra gradually increases with dopant concentration, and Photoluminescence (PL) spectroscopy study showed most intense emission around 1064 nm. Room‐temperature magnetic hysteresis curve in sample SSN2 showed ferromagnetism, slowly decreasing with Nd and becoming antiferromagnetic for higher compositions. Utilizing the absorption state observed in PL as metastable state makes it promising candidate for laser and IR detector application and the ferromagnetic/antiferromagnetic nature of sample makes it suitable candidate for spintronics device applications. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the effect of Na doping on the structural, microstructural and electrical properties of SrCeO3. With this goal, SrCe1−xNaxO3 (x = 0, 0.02, 0.04, 0.06 and 0.10) polycrystalline ceramics have been prepared using the solid-state route. The phase and structure of the synthesized samples were confirmed using X-ray diffraction technique. Rietveld refinement of the XRD profile confirmed that all the samples have orthorhombic structure and space group Pnma. Further, the purity of the synthesized samples was checked using Raman and Fourier transformation infrared (FTIR) spectroscopy techniques. The optical bandgap was calculated using UV–Vis technique, and the values were found 3.01 and 3.12 eV for pristine and Na doped samples. Scanning electron microscopic studies of fractured surfaces of the sintered pellets have indicated that dopant Na has played a significant role in grain growth. Grain size and morphology of Na doped samples is different from pristine SrCeO3. DC conductivity of Na doped samples is lower than undoped SrCeO3. [ABSTRACT FROM AUTHOR]

The reaction mechanism for the formation of Sr2SnO4 by solid-state reaction between SrCO3 and SnO2 has been investigated using thermal analysis (TG and DSC) combined with X-ray diffraction (XRD) techniques. It is observed that the formation of single-phase Sr2SnO4 takes place by reaction between SrO and SrSnO3 at temperatures ≥ 900 °C. Based on these studies, a few compositions of the system Sr2−xLaxSnO4 (x = 0.01, 0.02, 0.04, 0.06 and 0.10) have been synthesized by calcination at 1000 °C for 8 h. Rietveld refinement of the XRD data confirmed that all the synthesized samples have tetragonal structure, space group (I4/mmm) and symmetry group D4h17. The crystallite size and induced lattice strain has been calculated using size strain plot (SSP), varies from 30 to 50 nm and from (3.00 to 6.27) × 10−3, respectively. Raman and Fourier transformed infrared (FTIR) spectroscopy techniques have been utilized to ponder local changes in the structure of Sr2SnO4 with La incorporation. The optical properties of the samples have been studied using UV-Vis spectroscopy. The systematic shift in the position of the absorption edge (toward the higher wavelength) indicates the incorporation of La in the lattice of Sr2SnO4. The direct and indirect band gap of the samples calculated through Tauc's plot. The variation in the value of direct band gap is attributed to changes in the charge compensation mechanism or/reduction in particle size. [ABSTRACT FROM AUTHOR]

• The conventional ceramic route successfully synthesized all the samples. • Jonscher power law was applied to the ac conductivity of all samples to study the conduction mechanism. • The conductivity spectrum of all samples follows Ghosh and Rolling scaling. • Kohlrausch-William-Watt function was applied to M ″ (f) to study the relaxation mechanism of samples. • Both the scaling behaviors reflected the temperature-independent conduction mechanism in the system. The mixed ionic and electronic conductor oxide with formula Sr 2-x La x SnO 4 (S2LS) within x ≤ 0.10 were synthesized via the conventional ceramic route and investigated. The structural analysis revealed the formation of single-phase materials with a tetragonal crystal structure. The presence of Sn in the form of Sn4+/Sn2+ ions and oxygen vacancies in the synthesized samples were investigated by X-ray photoelectron spectroscopy. The alternating current (AC) conductivity and modulus spectra of S2LS systems were obtained as functions of frequency and temperature and further scaled. The AC conductivity data were analyzed using Jonscher's power law (JPL) fitting to determine the hopping frequencies, DC conductivities, and power exponents. The obtained activation energy value suggests the dependence of conductivity primarily on the mobility of charge carriers. The conductivity spectra were analyzed using various formalisms, viz., Ghosh scaling and Rolling scaling, to understand the conduction mechanism. The scaling behaviors of AC conductivity and modulus spectra reflect the temperature-independent conduction mechanism of the system. [Display omitted] The following graph shows Rietveld refinement XRD pattern, high-resolution scanning electron micrograph, scaled conductivity and scaled modulus as a function of frequency at different temperatures. [ABSTRACT FROM AUTHOR]

A few compositions of (Ba 1-x La x) 2 SnO 4 with 0 ≤ x ≤ 0.10 have prepared via solid-state ceramic route followed by calcination at 1000 °C for 8 h. The preliminary phase of samples has analyzed using XRD and found to be crystallized into tetragonal structure up to 4 atoms %. The solubility limit of La at Ba-site has reconfirmed using FTIR and Raman analysis. The AC conductivity spectra of single-phase samples follow universal Jonscher's power law σ a c = σ d c (1 + (f f h) n). Further, the thermal dependence of dc conductivity (σ d c) and hopping frequency (f h), indicating the presence of Arrhenius type charge transport in the samples. Ghosh scaling applied to σ a c of all temperatures found to superimpose on a single master curve, indicates the invariance of conduction mechanism. The impedance spectroscopy studies reflect the major contribution of grain in the conduction and relaxation process of all sample. Based on present study, the present material can be potentially used in semiconductor devices, UV-detector, and mixed ionic and electronic conductor (MIECs) by utilizing absorption states and thermo-curves as metastable state. • Single phase samples of Ba 2-x La x SnO 4 (0 = x ≤ 0.10) are synthesized at 1000 °C. • The solubility limit of La is analyzed by XRD, Raman, and UV–Vis. study. • The AC conductivity of single-phase samples follow universal Jonscher's power law. • AC conduction mechanism is explained using OLPT model. • Contribution of grain/grain boundaries is analyzed by Impedance spectroscopy. [ABSTRACT FROM AUTHOR]

Eu-doped Sr 2 SnO 4 samples were synthesized using conventional ceramic route, followed by calcination at 1000 °C. Rietveld refinement analysis of XRD data indicates that the samples are single phase and crystallized into tetragonal crystal structure. Functional groups and metal-oxygen interaction has been studied using FTIR spectroscopy. The XPS analysis revealed the presence of oxygen vacancy, Sr in Sr2+ and Sn in Sn2+/Sn4+ in sample. The PL spectrum shows five peaks of Eu3+ due to transition 5D 0 →7F 0,1,2,3,4. The transition peaks 5D 0 →7F 0 and 5D 0 →7F 2 found most intense in PL spectra, and their ratio with 5D 0 →7F 1 were increased up to SSE6 and then decreased for SSE10, due to quenching phenomenon. An efficient energy transfer from oxygen vacancy to 5D 0 →7F 0 state leads to enormously increase in their intensity. By utilizing these absorption states and emission states as metastable state, the present sample can be used in UV-filter, UV-detector, and optical device applications. [ABSTRACT FROM AUTHOR]

• Synthesis of single phase Ni 0.5 Co 0.5 Fe 2 O 4 nano-ferrites by using sol-gel technique. • Study of irreversible magnetic behavior with variable temperature and determination of micro-strain, retentivity and coercivity. • Demonstration of crystallite into cubic structure under spinel group by Rietveld refinement. • Determination of blocking temperature using Kneller's law. • Saturation magnetization at different temperature follows Bloch's law. In this paper, the irreversible magnetic behavior of Ni 0.5 Co 0.5 Fe 2 O 4 nano-ferrite has been discussed with varying the temperature. The nano-ferrite discussed in present work synthesized using sol gel technique. The formation of the phase of Ni 0.5 Co 0.5 Fe 2 O 4 was confirmed using X-ray diffraction (XRD), and their Rietveld refinement shows it crystallized into cubic structure with lattice constant 8.3541 Å under space group Fd 3 - m. The homogeneity and the morphology of the sample was analysed using FESEM along with EDAX measurement. The irreversibility of Ni 0.5 Co 0.5 Fe 2 O 4 was studied in three modes ZFCW, FCC and FCW using field dependent magnetic measurements in temperature range of 2 K–300 K under the presence of 50 Oe. However, the magnetic hysteresis of sample was studied at different temperature T = 5 K, 50 K, 100 K, 120 K, 200 K, 300 K from varying the field upto ±5 Tesla. Further, the asymmetry observed in the magnetization and demagnetization curve gives the value of H m , which increased with lowering the temperature due to magnetic crystalline phase as well as the micro-strain of the sample. Finally, retentivity, coercivity and saturation magnetization of the present sample makes it a potential candidate for magnetic memory devices, magnetic resonance imaging, medical diagnosis applications. [ABSTRACT FROM AUTHOR]

The samples of (Ba 1−x Sr x) 2 SnO 4 with x = 0, 0.10, 0.20, 0.40, 0.80, 1.00 were synthesized by a high-temperature solid state ceramic route. Lattice parameters obtained from the Rietveld profile analysis; decreased with increasing Sr. The decreasing nature of lattice parameters indicated the complete solubility of Sr at Ba-site. Further, incorporation of Sr at Ba-site has been studied by Fourier transform infrared (FTIR) spectroscopy. The dielectric constant and dissipation factor increases with increasing Sr. Contribution of grain and grain boundary were resolved by complex modulus spectroscopy analysis. AC conductivity spectra of the entire sample follow Universal Jonscher's power law. The similar value of activation energy obtained from relaxation frequency and dc conductivity implies that the origin of conduction and relaxation mechanisms remains the same throughout the samples. The modulus and conductivity spectra of solid solutions nicely follow the time-temperature superposition (TTSP) principle. Further, conductivity spectra of solid solutions were studied by Ghosh and Summerfield scaling. • The solubility of Sr in Ruddlesden popper system (Ba 1-x Sr x) 2 SnO 4 has achieved upto 100%. • Giant dielectric properties have been observed and compared to other layered perovskites. • Non-Debye type relaxation process occurred in the solid solution of Ruddlesden Popper system. • Relaxation and Conduction process takes place by hoping of electron between degenerate sites of Sn (Sn4+/Sn2+). • Scaling studies suggests that relaxation/conduction processes are temperature and compositional independent. [ABSTRACT FROM AUTHOR]

Powder of SrCe0.98Na0.02O3 is synthesized by calcination at 1000 °C for 8 h via solid‐state ceramic route. The ceramic/pellet of this compound is obtained by sintering at 1200 °C for 12 h. X‐ray diffraction (XRD) technique is used to confirm single‐phase formation. Rietveld refinement of the XRD pattern of sintered powder has confirmed orthorhombic crystal structure and space group Pnma as reported for SrCeO3. Further, the purity of the synthesized compound is ensured using Raman and Fourier transform infrared spectroscopy analysis. Scanning electron microscopic studies have reflected dense microstructure and spherical shape grains with an average size of 1.80 µm. Complex plane impedance and spectroscopic analysis are employed to study electrical conduction and relaxation mechanisms in the temperature range 300–600 °C and frequency range 20 Hz to 2 MHz. The activation energy for DC conduction (Econ) and relaxation (Erelx) is found to be the same (0.77 eV). Based on the numerical value of activation energies, conduction and relaxation mechanisms are attributed to migration of doubly ionized oxygen vacancies (VO••). [ABSTRACT FROM AUTHOR]