Sr Substitution Research Articles

Suppression of long-range ordering and multiferroicity in Sr-substituted Ba3−xSrxMnNb2O9 (x = 1 and 3)

Effects of Sr substitution at A-site in ordered perovskite Ba3−xSrxMnNb2O9 (x = 1 and 3) have been investigated using X-ray diffraction, magnetization, dielectric/magnetodielectric and neutron diffraction measurements. The parent compound Ba3MnNb2O9 having a large spin (S = 5/2) is known to exhibit type-II multiferroic properties with quasi 2D triangular lattice antiferromagnetic ground state. A slight perturbation in exchange interaction due to substitution of smaller size isovalent ion at the A-site in Ba3−xSrxMnNb2O9 (x = 1 and 3) has been found to alter the ground states drastically and hence the multiferroicity. The crucial role of various fluctuations (quantum and/or thermal), weak lattice distortion induced by Sr substitution and slight imbalance between different fluctuations in determining the ground states and the multiferroicity is discussed and compared with the results of smaller spin compounds (S = 1/2 or 1).

Glassy dielectric anomaly and negative magneto-capacitance effect in electron-doped Ca1−xSrxMn0.85Sb0.15O3

Manganites exhibit various types of electronic phenomena, and these electronic characteristics can be controlled by carrier doping. Herein, we report the dielectric and magnetic properties of electron-doped manganite Ca1−xSrxMn0.85Sb0.15O3 (x=0, 0.1, 0.2, and 0.3). The temperature dependence of the real part of the dielectric constant exhibits a broad and large peak just below the kink temperature of magnetization and a sharp decrease at lower temperatures, accompanied by an anomaly of the imaginary part. Furthermore, isovalent Sr substitution enhances the temperature of the dielectric peak by more than 50 K. Interestingly, the dielectric peak exhibits a negative magnetic-field effect. For all measured samples, the low-temperature variation of the dielectric constant can be qualitatively explained based on the Maxwell–Wagner (MW) model that describes a system composed of grain boundaries and semiconducting grains. However, the observed peak and its negative magneto-capacitance effect at high temperatures cannot be reproduced by a combination of the MW model and magnetoresistance effect. The dielectric peak strongly indicates polaronic relaxation in the present system. These results suggest that polarons form clusters with a dipole ordering and magneto-electric coupling, which might be consistently understood by the charge-ordering scenario.

Quantum liquid from strange frustration in the trimer magnet Ba4Ir3O10

Quantum spin systems such as magnetic insulators usually show magnetic order, but such classical states can give way to quantum liquids with exotic entanglement through two known mechanisms of frustration: geometric frustration in lattices with triangle motifs, and spin-orbit-coupling frustration in the exactly solvable quantum liquid of Kitaev’s honeycomb lattice. Here we present the experimental observation of a new kind of frustrated quantum liquid arising in an unlikely place: the magnetic insulator Ba4Ir3O10 where Ir3O12 trimers form an unfrustrated square lattice. The crystal structure shows no apparent spin chains. Experimentally we find a quantum liquid state persisting down to 0.2 K that is stabilized by strong antiferromagnetic interaction with Curie–Weiss temperature ranging from −766 to −169 K due to magnetic anisotropy. The anisotropy-averaged frustration parameter is 2000, seldom seen in iridates. Heat capacity and thermal conductivity are both linear at low temperatures, a familiar feature in metals but here in an insulator pointing to an exotic quantum liquid state; a mere 2% Sr substitution for Ba produces long-range order at 130 K and destroys the linear-T features. Although the Ir4+(5d5) ions in Ba4Ir3O10 appear to form Ir3O12 trimers of face-sharing IrO6 octahedra, we propose that intra-trimer exchange is reduced and the lattice recombines into an array of coupled 1D chains with additional spins. An extreme limit of decoupled 1D chains can explain most but not all of the striking experimental observations, indicating that the inter-chain coupling plays an important role in the frustration mechanism leading to this quantum liquid.

Tuning ferroelectricity by manipulating the global and local structure in a lead-free Sr-doped Ba(Ti1-x Snx)O3ceramics

The effect of 5% Sr substitution at the Ba site in Ba(Ti1-x Snx)O3 (BTSnx) system is investigated for , 0.075, and 0.12 compositions. The phase transition studies were carried out using dielectric, high-resolution X-ray diffraction, and PE hysteresis loop measurements. Rietveld refinements, along with dielectric studies on strontium-doped BTSnx reveal that the inter-ferroelectric phase boundaries observed in pure BaTiO3 approach the Tc line, with morphotropic phase boundary like behaviour. The PE hysteresis loops show enhanced polarization (≈ 190%) in Sr-doped BTSn5, which is attributed to the inter-ferroelectric phase instability (which facilitates polarization rotation, phase boundary motion, and domain wall motion), enhanced tetragonality (c/a), and increased unit-cell polarization evident from the amplitude of frozen phonon mode corresponding to the zone center of the cubic Brillouin zone. The ferroelectric polarization observed in the average-cubic-structure state of Sr-doped BTSn12 is attributed to the cooperative polar off-centre displacements of A (Ba2+/Sr2+) and B (Ti4+/Sn4+) site cations along and directions, respectively. Further, Sr-doped BTSn12 has high dielectric constant and low loss which makes this material an important composition for various technological applications.

Mineralization of bioactive marine sponge and electrophoretic deposition on Ti-6Al-4V implant for osteointegration

Surgical grade Ti-6Al-4V is considered to be the most attractive material in the medical field, but their low bioactivity, post-surgery infection, and poor osteointegration are a major drawback. Bioactive coating of the titanium alloy implant, increases the cell proliferation, biocorrosion, bioactivity, roughness with excellent antibacterial nature. In the present study, multi-minerals modified calcium silicate prepared by controlled substitution of Sr, Zn, Mg, Ce into calcium silicate. Additionally, a synergistic combination of the Hyatella cribriformis marine sponge, and mineral-calcium silicate electrolyte used for electrophoretic deposition on Ti-6Al-4V. Ceramic nanocomposite coating forms a homogenous layer with a higher distribution of mineral-sponge on the surface. Electron microscopy studies report-good structural stability of nanocomposites coating on the substrate surface due to functionalization and cross-linking. Coating form lower corrosion current density of 4.7× 10−7 A/cm−2 for sponge-mineral-CaSiO3 coating. Subsequently, the biological performances of the assemblies show drastic improvement in apatite formation in 15 days. The coating was biocompatible, and it displays a high cell proliferation rate at 10 μg/mL concentration. Coated hybrid surface enhances the osteoinductivity, mineralization of the extracellular matrix and filopodia formation. Improved antibacterial multifunctionality of sponge-ceramic coating exhibited the zone of inhibition of 16 mm, 13 mm for S. aureus, and E. coli at 50 μg/mL concentration. Therefore, the electrophoretic deposition of the sponge-Sr-Zn-Mg-Ce minerals incorporated calcium silicates coating, would successfully enhance the bone regeneration.

Effect of Sr substitution on the luminescence of Pr-activated Ca2-xSrxLaNbO6

The effect of Sr substitution on the luminescence of Pr-activated Ca2-xSrxLaNbO6 was investigated. The samples were prepared by solid-state reaction. The Ca2LaNbO6 phase was confirmed in the samples with x = 0–1.5 by the X-ray diffraction. With increasing x, lattice constant β which is an angle between a and c axes in monoclinic structure decreased from 89.69°, reached its minimum value of 89.06° at x = 0.9, and increased. The emission peak of the samples excited at 450 nm was observed at 500 nm, 544 nm, 622 nm and 655 nm. The emission intensity at 655 nm showed a negative correlation with β. It was found that the decrease in lattice constant β had a significant effect in the improvement of the emission intensity.

Enhanced thermoelectric properties of Ca3Co4O9+δ ceramics by Sr substitution

Ca3-xSrxCo4O9+δ (CCO-Srx) with varying strontium (Sr) content (x = 0.4, 0.5, 0.6, and 0.7) were synthesized by solid-state method. The crystal structures and morphologies of Ca3-xSrxCo4O9+δ thermoelectric ceramics were analyzed by XRD and SEM. Micro structural characterizations have shown that all samples are composed by the same oriented plate-like grains with similar sizes about 1–3 μm diameters and 0.2–0.5 μm thicknesses. The results of XRD have shown that no secondary phases have been produced, which indicated that Sr has been incorporated into the Ca3Co4O9 phase. The diffraction peak (00l) shifted to a lower angle and the offset is increasing with the increase of Sr content, which indicated that the Sr cations can enter the Ca-sites of the Ca3-xSrxCo4O9+δ, and cause increase of the length of the C axis. Slight improvements in the Seebeck coefficient (S) and electrical resistivity (ρ) were observed across all Sr-substitution samples when the mol% of Sr was adjusted. The improvement in both electrical resistivity and Seebeck coefficient leads to higher power factor (PF) values for the ceramics. The measured results show that the highest power factor value around 0.21 mW m−1K−2 can be obtained in Ca2.4Sr0.6Co4O9+δ at 650 °C, which is 16.7% higher than the undoped sample, The ZT value of 0.37 at 650°Cfor the CCO–Sr0.6 sample is significantly higher than that of the pure CCO sample. The results show that Sr can be as an effective doping element to reduce the thermal conductivity and enhance the Seebeck coefficient for the CCO system. It can be concluded that x = 0.6 is the optimal Sr for Ca substitution in this material system.

Preparation of Sr-substituted Hydroxyapatite Nanorods for Liquid Crystal Phase Transition

A citrate-assisted hydrothermal method was utilized for the preparation of Sr-substituted hydroxyapatite (HA) nanoparticles. The influences of Sr-substituting degree on the phase identifications, microstructures and colloidal stability of the resultant products were studied. The experimental results show that the crystalline structures and morphologies of final resultants are significantly changed by controlling the Sr-substituting degree. As the Sr-substituting degree increases, the colloidal stability of samples first increases and then decreases rapidly; the morphology of the product first changes from nanorods to short nanorods rod and then becomes nanowires. Uniform HA hexagonal nanorods with high aspect ratio (>4.0) and excellent aqueous colloidal stability were prepared by 6 h hydrothermal reaction at 180 °C without Sr substitution. The dispersion underwent the phase transition from isotropic to liquid-crystalline state upon the increasing concentration of 25wt% and the complete liquid-crystalline phase was achieved when at the concentration above 31wt%. These novel findings provide new insights into the role of Sr substitution on both the citrate-assisted hydroxyapatite crystallization and tailoring of colloidal stability. Moreover, HA liquid crystal behavior was successfully observed, which lays a foundation for the fabrication of macroscopically assembled hydroxyapatite-based biomimetic materials for biomedical applications.

Long-range and local crystal structures of the Sr1−xCaxRuO3 perovskites

The crystal structures of the Sr1-xCaxRuO3 perovskites are investigated using both long range and local structural probes. High resolution synchrotron powder X-ray diffraction characterization at ambient temperature shows that the materials are orthorhombic to high precision, and we support previous work showing that Ca2+ substitution for Sr2+ primarily changes the tilting of rigid corner-sharing RuO6 octahedra at their shared oxygen vertices. X-ray pair distribution function analysis for SrRuO3, CaRuO3 and one intermediate composition show them to be locally monoclinic, and no long range or local phase transitions are observed between 80 and 300 K for materials with intermediate compositions. High-resolution transmission electron microscopy shows that the Sr/Ca distribution is random at the nanoscale. We plot magnetic characteristics such as the ferromagnetic Tc, Curie-Weiss theta, effective moment, and ambient temperature susceptibility vs. the octahedral tilt and unit cell volume.

Analysis of the magnetic and magnetocaloric properties of ALaFeMnO6 (A = Sr, Ba, and Ca) double perovskites

In previous studies, we have reported that double perovskite La2NiMnO6 presents non-negligible potential for room temperature magnetocaloric tasks. With the aim of improving even further the cooling performances and the working temperature range of double perovskites, we report the magnetic and magnetocaloric properties of La2MnFeO6 and ALaMnFeO6 (A = Sr, Ba, and Ca) compounds. X-ray diffraction and Rietveld refinement show that La2MnFeO6 (LMFO) and CaLaMnFeO6 (CLMFO) samples crystallize in an orthorhombic structure with the Pnma space group. However, a rhombohedral structure with the R3¯C space group is obtained for BaLaMnFeO6 (BLMFO) and SrLaMnFeO6 (SLMFO) samples. Substituting La by Ba or Sr in LMFO leads to a clear increase of the Curie temperature (Tc) compared to LMFO from 150 K for BLMFO up to 350 K for SLMFO. Moreover, CLMFO shows the smallest Tc down to 70 K. Ferromagnetic-like behavior is observed for SLMFO and BLMFO, while CLMFO's magnetism resembles that of LMFO. A clear connection between the structural parameters and the magnetic properties of these doped LMFO samples is unveiled as the highest Tc and the largest magnetization are observed for SLMFO which also shows bond angles closest to 180° and the smallest bond lengths, thus optimizing the superexchange interaction. The partial substitution of Sr for La leads, in fact, to a significant magnetocaloric effect over a wide operating temperature range extending beyond 300 K. For some optimal growth conditions, its entropy change varies slowly over an unusually large temperature range, which is of clear interest from a practical point of view.

Strontium modulates osteogenic activity of bone cement composed of bioactive borosilicate glass particles by activating Wnt/β-catenin signaling pathway

There is a need for synthetic grafts to reconstruct large bone defects using minimal invasive surgery. Our previous study showed that incorporation of Sr into bioactive borate glass cement enhanced the osteogenic capacity in vivo. However, the amount of Sr in the cement to provide an optimal combination of physicochemical properties and capacity to stimulate bone regeneration and the underlying molecular mechanism of this stimulation is yet to be determined. In this study, bone cements composed of bioactive borosilicate glass particles substituted with varying amounts of Sr (0 mol% to 12 mol% SrO) were created and evaluated in vitro and in vivo. The setting time of the cement increased with Sr substitution of the glass. Upon immersion in PBS, the cement degraded and converted more slowly to HA (hydroxyapatite) with increasing Sr substitution. The released Sr2+ modulated the proliferation, differentiation, and mineralization of hBMSCs (human bone marrow mesenchymal stem cells) in vitro. Osteogenic characteristics were optimally enhanced with cement (designated BG6Sr) composed of particles substituted with 6mol% SrO. When implanted in rabbit femoral condyle defects, BG6Sr cement supported better peri-implant bone formation and bone-implant contact, comparing to cements substituted with 0mol% or 9mol% SrO. The underlying mechanism is involved in the activation of Wnt/β-catenin signaling pathway in osteogenic differentiation of hBMSCs. These results indicate that BG6Sr cement has a promising combination of physicochemical properties and biological performance for minimally invasive healing of bone defects.

Molecular Dynamics Simulation of Structural and Transport Properties of Solid Solutions of Double Perovskites Based on PrBaCo2O5.5

The oxygen diffusion has been simulated by the molecular dynamics method in the solid solutions of PrBaCo2O5.5-based double perovskites: PrBa0.5Sr0.5Co2O5.5 with random substitution of half of Ba atoms by Sr atoms, PrBa0.5Sr0.5CoFeO5.5 with random substitution Ba → Sr and Co → Fe, PrBa0.5Sr0.5CoCuO5.5 with random substitution Ba → Sr and Co → Cu, and PrBa0.5Sr0.5CuFeO5.5 with random substitution Ba → Sr and random substitution of Co atoms by Fe and Cu atoms. It is shown that, varying the oxygen nonstoichiometry and/or chemical composition of solid solutions based on PrBa0.5Sr0.5Co2O5.5, one can significantly change the coefficient of thermal expansion of the materials. It is established for the first time that the maximum difference between the mobilities of oxygen atoms of different types observed in PrBa0.5Sr0.5Co2O5.5 significantly decreases at partial substitutions of cobalt by iron and copper. In the PrBa0.5Sr0.5CuFeO5.5 solid solution, the oxygen atom mobility in the (Cu,Fe)–O layers becomes somewhat higher than that in the Pr–O layers.

Probing the Griffiths like phase, unconventional dual glassy states, giant exchange bias effects and its correlation with its electronic structure in Pr2−xSrxCoMnO6

Crystal, electronic structure, dc and ac magnetization properties of the hole substituted (Sr2+) and partially B-site disordered double perovskite Pr2−xSrxCoMnO6 system have been investigated. The XRD pattern analysis showed a systematic decrease in the lattice parameters owing to the enhanced oxidation states of the Co/Mn ions. The electronic structure study by XPS measurements suggested the presence of mixed valence states of the B-site ions (Co2+ /Co3+ and Mn3+ /Mn4+) with significant enhancement of the average oxidation states due to hole doping. The mere absence of electronic states near the Fermi level in the valence band (VB) spectra for both pure (x = 0.0) and Sr doped (x = 0.5) systems indicated the insulating nature of the samples. Sr substitution is observed to increase the spectral weight near the Fermi level suggesting for an enhanced conductivity of the hole doped system. The dc magnetization data divulged a Griffiths like phase above the long-range ordering temperature. A typical re-entrant spin glass like phase driven by the inherent anti-site disorder (ASD) has been recognized by ac susceptibility study for both the pure and doped systems. Most interestingly, the emergence of a new cluster glass like phase (immediately below the magnetic ordering temperature and above the spin-glass transition temperature) solely driven by the Sr substitution has been unravelled by ac magnetization dynamics study. Observation of these dual glassy states in a single system is scarce and hence placed the present system amongst the rare materials. The isothermal magnetization measurements further probed the exhibition of the giant exchange bias effect originated from the interfacial exchange interactions due to existence of low temperature antiferromagnetic clusters embedded in the glassy matrix.

Effect of Sr substitution on the air-stability of perovskite solar cells

By using a two-step spin-coating method, 10 mol% SrI2 and 10 mol% SrCl2-substituted perovskite films were synthesized and utilized to construct mesoscopic perovskite solar cells (PSCs), respectively. The influences of Sr substitutions on the humidity and thermal stability of PSCs were systematically investigated. It is indicated that both 10 mol% SrI2 substitution and 10 mol% SrCl2 substitution can enhance the power conversion efficiency (PCE) of PSC to more than 15%. The 10 mol% SrCl2 substitution can improve the humidity resistance of perovskite films, which is conducive to inhibiting the increase of perovskite's defect density caused by humidity. After storing at 20 ± 5 °C, 30 ± 5%RH for 21 d, the 10 mol% SrCl2-substituted PSC can still maintain 84% of the initial efficiency. However, the 10 mol% SrI2-substituted PSC exhibits a strong humidity sensitivity, which results in the increase of series resistance and the decrease of recombination impedance, thus making the PCE decrease to less than 20% of the initial value after storing at 20 ± 5 °C, 30 ± 5%RH for 21 d. As for the thermal stability of PSCs, both the 10 mol% SrI2 and 10 mol% SrCl2-substituted perovskite films exhibit a certain thermal resistance. After 18 thermal cycles, both the 10 mol% SrI2 and 10 mol% SrCl2-substituted PSCs can maintain over 90% of the initial PCEs.

Size, disorder, and charge doping effects in the antiferromagnetic series Eu1-xAxGa4 (A = Ca, Sr, or La)

EuGa4 hosts a magnetic Eu2+ sublattice surrounded by a network of covalently-bound Ga atoms with the BaAl4 structure type (space group I4/mmm). In this study, we present the synthesis and characterization of three new single crystal substitutional series EuAx1−xGa4 with A ​= ​Ca, Sr, or La. X-ray diffraction and resistivity measurements show that Ca substitution induced a structural phase transition from the tetragonal crystal structure at high temperatures to the monoclinic crystal structure (CaGa4 type, space group C2/m) at low temperatures and suppressed the antiferromagnetic ordering temperature to 8.8 ​K for x ​= ​0.45. Comparatively, La or Sr substitution maintained the tetragonal crystal structure and suppressed the antiferromagnetic ordering temperatures to 6.7 ​K and 1.6 ​K for (A, x) = (La, 0.37) and (Sr, 0.91), respectively. In addition to suppressing the magnetic order, magnetization and specific heat measurements indicate the onset of anisotropic metamagnetic transitions in (La, 0.18), (La, 0.37), and (Sr, 0.63), along with an incommensurate-to-commensurate magnetic transition in (Sr, 0.38). By comparing these effects of doping EuGa4, we show how size, disorder, and charge determine the structure-physical property relations in EuGa4.

Efficient Nanorod Array Perovskite Solar Cells: A Suitable Structure for High Strontium Substitution in Nature.

Organic-inorganic hybrid perovskite solar cells (PSCs) have become a research hotspot because of their excellent power conversion efficiency (PCE), but the presence of toxic lead (Pb) in perovskite films has significantly limited their commercial applications. In this study, using a TiO2 nanorod array (TNRA) as the electron transport layer, strontium chloride (SrCl2) was chosen to fabricate lead-less PSCs in air (relative humidity, RH = 50%) by a simple two-step spin-coating method. The influence of introduced strontium (Sr) on the perovskite films and cell properties was systematically investigated by various characterization methods. With an increasing Sr substitution amount from 0 to 15 mol %, the formed perovskite films with a compact structureand large crystalline size essentially remained invariable, while the amount of residual PbI2 was reduced, which is beneficial for the cell performance. An optimal PCE of 16.08% (average PCE = 15.37%) was obtained for the 5 mol % Sr-substituted PSCs because of the enhanced charge extraction from the perovskite films to the TNRAs and the suppressed charge recombination in the PSCs. Both the humidity and thermal stability of the Sr-substituted PSCs were improved. More importantly, the 15 mol % Sr-substituted PSCs still exhibited a PCE of 15.09% in air (RH = 50%), maintaining 99% of the cell efficiency of the pristine (0 mol % Sr) PSC (15.27%), suggesting that the structure of TNRAs is suitable for the synthesis of high-performance Sr-substituted lead-less PSCs.

Structure and in vitro dissolution of Mg and Sr containing borosilicate bioactive glasses for bone tissue engineering

Borosilicate bioactive glasses are promising for bone tissue engineering. The objective was to assess the impact of magnesium and/or strontium, when substituted for calcium on the glasses' thermal and dissolution properties. Both Mg and Sr substitution appeared to enhance the hot forming domain, i.e. the ability to hot process (sinter, draw fibres) without adverse crystallization. Structural analysis indicated that substitution of MgO and/or SrO for CaO results in changes in the BO3/BO4 ratio as well as in the ratio between bridging and non-bridging oxygen atoms in the silicate structure. Additionally, a de-shielding effect was noticed when Ca, Mg and Sr are present together in the glass network, possibly owing to PO43− charge-balanced preferentially by Na+. The Mg and/or Sr substitution resulted in a lower ion release in simulated body fluid and delayed formation of hydroxyapatite. However, once this layer formed it consisted of a Mg/Sr-substituted apatite. This work highlights the effect of combined ionic substitutions on bioactive glass structure and properties.

Study of transport, magnetic and magnetocaloric properties in Sr2+ substituted praseodymium manganite

The magnetotransport, magnetic and magnetocaloric properties in the polycrystalline Pr1−xSrxMnO3 (0.20 ≤ x ≤ 0.40) have been studied. The X-ray diffraction peaks for the composition x = 0.20, 0.33 and 0.40 have been indexed with orthorhombic structure having Pnma space group, whereas x = 0.25 composition has been indexed to R-3c space group having rhombohedral symmetry. The substitution of Sr2+ at Pr3+site shows an increase in metal-insulator transition temperature (TMI) and ferromagnetic ordering temperature (Tc). The composition, x = 0.25 shows the higher isothermal magnetic entropy change, = 2.84 J kg−1K−1 with RCP = 116.33 J kg−1 at ∆H = 3 Tesla. The high RCP value (=151.16 J kg−1) with = 2.41 J kg−1 K−1 at ∆H = 3 Tesla for the composition, x = 0.40, implies that plays a significant role.

Structural, Thermal, Electrical and Dielectric Properties of La1-xSrxMn0.50Fe0.50O3 {0.10 ≤ x ≤ 0.40} Cathode Material for Solid Oxide Fuel Cells

La1-xSrxMn0.50Fe0.50O3 {0.10 ≤ x ≤ 0.40} perovskite ceramics material is prepared by solid-state reaction method and samples are characterized to study their structural, thermal, electrical and dielectric properties. X-ray diffraction results show that as prepared samples are well crystallized in single phase and have rhombohedral crystal structure. Density is measured by Archimedes principle and with Sr substitution its value decreasing. Thermogravimetric analysis shows the weight gain in the material above 300 ºC. Thermal expansion coefficient value for x = 0.10 and 0.40 composition is found to be 12.9 × 10-6 ºC−1 and 11.3 × 10-6 ºC−1, respectively upto 800 ºC. Impedance analyzer is used to study dielectric and electrical properties which show that all the as prepared samples obey non-Debye relaxation behaviour. The maximum conductivity value is 121.09 S cm-1 for x = 0.10 and 155.96 S cm-1 for x = 0.40 at 600 ºC and 303.59 S cm-1 for x = 0.10 and 362.35 S cm-1 for x = 0.40 at 800 ºC which confirmed that in the experimental perovskite the conductivity increases after Sr doping. Activation energy also found to be decreases with Sr substitution. Therefore, studied properties confirmed that the as-prepared material is a suitable cathode material for intermediate temperature solid oxide fuel cells (SOFCs).

Structural evolution, electrochemical kinetic properties, and stability of A-site doped perovskite Sr1−xYbxCoO3−δ

Structural evolution occurs upon A-site partial substitution of Sr by Yb in SrCoO3−δ, leading to enhanced performance and stability.