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The aim of this study was to develop celecoxib (CLX) -polyvinylpyrrolidone (PVP) solid dispersion nanoparticles with and without surfactant using the supercritical antisolvent (SAS) process. The effect of different surfactants such as gelucire 44/14, poloxamer 188, poloxamer 407, Ryoto sugar ester L1695, and D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) on nanoparticle formation and dissolution as well as oral absorption of CLX -PVP K30 solid dispersion nanoparticles was investigated. Spherical CLX solid dispersion nanoparticles

NO is a gas and has a very short half-life (3-5s), as it is highly reactive. No and its products are inactivated through oxidation into nitrite (NO2-) and nitrate (NO3-) Which is excreted in the urine. NO is regarded as magical molecule which has profound role in regulation of various function in various organs of human body and in health and disease. Here in this review article authors has discussed about its chemistry and metabolism, its discovery, its basic functions, role in pathophysiology of various diseases and its therapeutic implications.

The control on magnetization via applied electric field is the centre of attention in multiferroic materials for the achievement of technological device applications. The bismuth ferrite (BiFeO3) is best multiferroic material which has the ferroelectric as well as weak magnetic nature simultaneously in the single phase near the room temperature. There are many unsolved problems in the path of the actual device applications of multiferroic BiFeO3 (BFO) due to the transformation of several scientific progresses into technical innovations. So, there is a need to solve these complications via focused research movements, which may convert this useful material into actual device applications. This review article is mainly concentrated on look over the recent advances on technological achievements and challenges in BFO via the magnetoelectric coupling and presents the latest devices achievements.

This paper presents synthesis and study of Structural, Optical, and Photocatalytic properties of bismuth ferrite (BFO) and nickel doped bismuth ferrite (BiFe1-xNixO3) nanoparticles. The synthesis of BiFeO3 and BiFe1-xNixO3 (x = 0.02, 0.04) are done by Sol-Gel method. After synthesis the samples of pure and transition metal ion (Ni) doped bismuth ferrite have been studied by using X-ray diffractometer (XRD), X-ray Photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope and Raman Spectroscopy. Optical properties are studied by using UV–vis spectroscopy using different wavelengths (range 300–800 nm). Photocatalytic properties are also studied by degradation of MB dye using prepared samples as photocatalyst. XRD patterns shows that all the prepared samples are crystalline and crystallinity increased by Ni-doping and shifts in XRD peaks by Ni-doping shows the distortion in the structure of BFO. Raman spectroscopy also indicates the rhombohedral distorted structure of Ni-doped BFO in R3C space group. FESEM micrographs shows that Ni-doped BFO has polyhedral and spherical shape grains and Ni doping cause reduction in grain size. Optical band gap reduced due to Ni-doping is shown by the UV–Vis spectroscopy results and Tauc’s plots. The increase in reduction of MB dye due to Ni-doping shows the enhanced photocatalytic properties of BFO by Ni doping.

In this study, multifunctional lithium-doped bismuth ferrite [BiFe1−xLixO3]-graphene nanocomposites (x = 0.00, 0.02, 0.04, 0.06) were synthesized by a sol-gel and ultrasonication assisted chemical reduction method. X-ray diffraction and FESEM electron microscopy techniques disclosed the nanocomposite phase and nanocrystalline nature of [BiFe1−xLixO3]-graphene nanocomposites. The FESEM images and the EDX elemental mapping revealed the characteristic integration of BiFe1−xLixO3 nanoparticles (with an average size of 95 nm) onto the 2D graphene layers. The Raman spectra of the [BiFe1−xLixO3]-graphene nanocomposites evidenced the BiFe1−xLixO3 and graphene nanostructures in the synthesized nanocomposites. The photocatalytic performances of the synthesized nanocomposites were assessed for ciprofloxacin (CIP) photooxidation under UV-visible light illumination. The photocatalytic efficiencies of [BiFe1−xLixO3]-graphene nanocomposites were measured to be 42%, 47%, 43%, and 10%, for x = 0.00, 0.02, 0.04, 0.06, respectively, within 120 min illumination, whereas the pure BiFeO3 nanoparticles were 21.0%. BiFe1−xLixO3 nanoparticles blended with graphene were explored as cathode material and tested in a microbial fuel cell (MFC). The linear sweep voltammetry (LSV) analysis showed that the high surface area of BiFeO3 was attributed to efficient oxygen reduction reaction (ORR) activity. The increasing loading rates of (0.5–2.5 mg/cm2) [BiFe1−xLixO3]-graphene composite on the cathode surface showed increasing power output, with 2.5 and 2 mg/cm2 achieving the maximum volumetric power density of 8.2 W/m3 and 8.1 W/m3, respectively. The electrochemical impedance spectroscopy (EIS) analysis showed that among the different loading rates used in this study, BiFeO3, with a loading rate of 2.5 mg/cm2, showed the lowest charge transfer resistance (Rct). The study results showed the potential of [BiFe1−xLixO3]-graphene composite as a cost-effective alternative for field-scale MFC applications.

Aims – The study aims to compare the efcacy of bolus intravenous clonidine and esmolol for attenuation of hemodynamic responses associated with laryngoscopy and endotracheal intubation. AfterMethod- institutional ethical committee approval 72 adult ASA I and ASA II patients of both sex were included in this study who went elective abdominal surgery under general anaesthesia were divided into two groups. Group-A (clonidine) receiving bolus dose of 1 microgram/kg clonidine, Group-B(esmolol) receiving bolus dose of 1mg/kg esmolol. All patients were given injection fentanyl 2microgram/kg before induction of anaesthesia. Heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure were recorded as baseline, before study drug, after study drug, just before intubation, 1,3,5,and 10 minute thereafter. Demographic data and baseline hemodynamic parameters were comparable among each group. The riseResult- in heart rate was better controlled in esmolol group and was statistically signicant. There was no signicant rise in blood pressure in clonidine Group and it came to the baseline level within 1 minute post intubation and was statistically signicant Conclusion- Esmolol 1mg/kg was a better drug to control increase in heart rate but pressure response was better controlled by clonidine 1microgram/kg .Hemodynamic parameters were better maintained throughout the procedure by clonidine.

The present study explores the use of carbon dots coated with Iron (II, III) oxide (Fe3O4) for its application as an anode in microbial fuel cells (MFC). Fe3O4@PSA-C was synthesized using a hydrothermal-assisted probe sonication method. Nanoparticles were characterized with XRD, SEM, FTIR, and RAMAN Spectroscopy. Different concentrations of Fe3O4- carbon dots (0.25, 0.5, 0.75, and 1 mg/cm2) were coated onto the graphite sheets (Fe3O4@PSA-C), and their performance in MFC was evaluated. Cyclic voltammetry (CV) of Fe3O4@PSA-C (1 mg/cm2) modified anode indicated oxidation peaks at −0.26 mV and +0.16 mV, respectively, with peak currents of 7.7 mA and 8.1 mA. The fluxes of these anodes were much higher than those of other low-concentration Fe3O4@PSA-C modified anodes and the bare graphite sheet anode. The maximum power density (Pmax) was observed in MFC with a 1 mg/cm2 concentration of Fe3O4@PSA-C was 440.01 mW/m2, 1.54 times higher than MFCs using bare graphite sheet anode (285.01 mW/m2). The elevated interaction area of carbon dots permits pervasive Fe3O4 crystallization providing enhanced cell attachment capability of the anode, boosting the biocompatibility of Fe3O4@PSA-C. This significantly improved the performance of the MFC, making Fe3O4@PSA-C modified graphite sheets a good choice as an anode for its application in MFC.

Samples with stoichiometry Zn1–xCdxAl2O4 (x = 0.00–0.70) were synthesized by epoxide-mediated gel method. The formation of spinel was inferred from the powder X-ray diffraction (PXRD) patterns of samples. The inversion parameter determined from 27Al NMR spectral analysis were found to be 0.06 and 0.38. The higher inversion character was also supported by their Raman spectra. The direct bandgap was found to be from 3.81 eV (ZnAl2O4) to 4.70 eV (70 mol% Cd2+-substituted sample). The paramagnetic character of these oxygen vacancies was deduced from electron paramagnetic spectrum at room temperature. From temperature-dependent dielectric measurements (120–400 K), transition from ferroelectric to paraelectric phase transition was observed for Cd2+-substituted sample. Enhancement in oxygen ion conductivity to an extent of five orders of magnitude was observed for the Cd2+-substituted samples at 773 K. From the estimated activation energy values, thermal motion of oxygen vacancies was attributed for this conductivity.

Bi1-xSmxFeO3 (x = 0.00, 0.05, 0.15) nanoparticles have been prepared through tartaric acid assisted sol–gel method. The X-ray diffractogram was used to confirm the phase formation and it revealed the single-phase formation with R3c space group. SEM analysis revealed that the particle size decreased with increasing Sm concentration. The crystallite size was observed to be in the range of 30 nm. M-H study depicted an increase in magnetization with increasing samarium concentration. Electron paramagnetic resonance (EPR) of magnetization studies was found to be in agreement with results of the vibrating sample magnetometer (VSM) magnetization studies.

We have reported the influence of Na substitution on structural, magnetic, optical and photocatalytic properties of sol–gel route synthesized Bi1−xNaxFeO3 (x = 0.0, 0.02, 0.04, 0.06 and 0.08) nanoparticles. Rietveld refinement of the XRD data and electron microscopy techniques revealed the phase purity and nanocrystalline nature of Bi1−xNaxFeO3 samples. The substitution of Na1+ leads to the structural distortion in BiFeO3 nanoparticles which is apparent from the XRD Rietveld refinement and Raman spectroscopy studies. The ferromagnetic ordering parameters increase with increasing Na content in BiFeO3 nanoparticles and the highest magnetization 0.91 emu/g at 30kOe is observed for x = 0.08 sample. The observed enhanced ferromagnetic behaviour of Bi1−xNaxFeO3 nanoparticles are also endorsed by the ESR analysis. The energy bandgap of BiFeO3 nanoparticles is altered by aliovalent Na ions substitution from 2.16 to 2.03 eV. Compared to pristine BiFeO3, the Na-substituted BiFeO3 nanoparticles revealed the much-advanced photocatalytic activity of methylene blue (MB) and crystal violet (CV) under UV–visible light irradiation. In the irradiation time of 100 min, Bi0.96Na0.04FeO3 nanoparticles showed ~ 95% MB and ~ 84% CV degradation. The outstanding changes in the magnetic and photocatalytic properties of Bi1−xNaxFeO3 nanoparticles are due to the differences in the ionic radii, aliovalency between the Bi3+ and Na1+ ions and oxygen vacancies.

Multiferroics are the materials having ferroelectric and magnetic properties simultaneously and can be tuned by controlling electric and magnetic field for the desired applications. Pure and samarium-doped bismuth ferrite nanoparticles Bi1−xSmxFeO3 (BSFO x = 0, 0.05, 0.10, 0.15, 0.20) with varied doping concentrations have been synthesized using sol–gel technique. The effect of doping on structural, morphological, elemental composition and optical properties were analyzed using various characterization techniques. X-ray diffraction (XRD) analysis of Bi1−xSmxFeO3 samples show the compressive lattice distortion and structural phase transformation from rhombohedral to orthorhombic phase. The Rietveld refinement shows that the crystalline structure of pristine BiFeO3 (BFO) is typical rhombohedral structure with R3c space group. Scanning electron micrograph (SEM) reveals that with increasing Sm concentration the grain size decreases up to ~ 30 nm. XRD and SEM analysis confirmed the synthesized samples having pure phase formation and nanocrystalline nature. Ultraviolet–Visible (UV–Vis) spectra of the samples show that the enhanced visible light absorption would be a promising material for photocatalytic application. The findings of X-ray photoelectron spectroscopy (XPS) verify the effective Sm doping in BFO samples.

A detailed study on synthesis and optical, magnetic, dielectric, and photocatalytic properties of Multiferroic co-doped Bi1−xSmxFe1−xNixO3 (x = 0.00, 0.02, 0.04, 0.06 and 0.08) (BSFNO) nanoparticles that have been prepared by tartaric acid-based sol–gel technique has been conducted. X-ray diffraction data show that high crystallite could be provided by the sharp peak and mergers of the doublet peaks, for instance (104) and (110), and (006) and (202), which indicates structural transition and XRD pattern shift towards higher angle, indicating structural distortion due to Sm and Ni co-doped BiFeO3. Raman spectroscopy also gives the confirmation of structural distortion and distorted rhombohedral perovskite structure with R3c symmetry. FESEM studies have revealed microstructural and nanocrystalline nature of BSFNO, a nanostructured material, and elemental analysis was done by EDX. The particle size of BSFNO (x = 0.02, 0.04) was analyzed by TEM and the average size of the particle was found to be ~ 50 nm. The identification of elements, chemical shift, oxidation state of elements ,and oxygen vacancies of the Sm and Ni co-doped BiFeO3 (x = 0.02 and 0.06) samples were analyzed by XPS. The calculated energy band gap values for BSFNO, a nanostructured material, were found to be 2.3 eV, 2.03 eV, 2.04 eV, 2.03 eV, 2.04 eV, respectively (from UV–VIS spectra). These results provide preliminary research for optoelectronic device and infrared detector. An enhancement in saturation magnetization has been observed with the substitution of Sm and Ni co-doped in BFO. Similarly enhancement in the dielectric constant (e) and dielectric loss (tanδ) has been observed with the substitution of Sm and Ni co-doping in BFO. The photocatalytic properties enhanced in co-doped BSFNO in comparison to pure BFO. The % efficiency and degradation of co-doped BSFNO increases when compared to pure BFO.

Sol-gel synthesized Sm and Ni substituted bismuth ferrite (Bi1−xSmxFe1−xNixO3, x = 0.04) particles were summed up with ZnO by reflexing method. X-ray diffraction and field emission scanning electron microscopy were used for structural and microstructural studies. The XRD outcome exposed the coating of ZnO on distorted rhombohedral (R3c) structured Sm and Ni substituted BiFeO3. The particle size of Sm and Ni substituted BiFeO3 nanoparticles were estimated to be 50–90 nm. The grain size and surface morphology of Bi1−xSmxFe1−xNixO3 (x = 0.04) @ZnO nano composite was studied from FESEM micrographs. Elemental analysis was done by EDX. The energy band gap was found to be ∼ 2.00 eV for Bi0.96Sm0.04Fe0.96Ni0.04O3 and ∼2.35 eV for ZnO (from UV–VIS spectra). It was detected that the optical absorption was higher for Bi0.96Sm0.04Fe0.96Ni0.04O3@ZnO nano composite than Bi0.96Sm0.04Fe0.96Ni0.04O3 nanoparticles. The photocatalytic degradation efficiency for Bi0.96Sm0.04Fe0.96Ni0.04O3@ZnO nano composite was found to be higher than Bi0.96Sm0.04Fe0.96Ni0.04O3 nanoparticles.

An efficient route for the synthesis of triazole containing triaryl-1H-imidazole (3a–3r) was achieved involving multicomponent condensation of triazole aldehydes, ammonium acetate and 1,2-dicarbonyl compounds in glacial acetic acid. The structure of newly synthesized imidazoles was established by the FTIR, HRMS and NMR spectra. All the compounds displayed considerable antimicrobial activity against fungal and bacterial strains. The triazolyl imidazole 3p was substantially potent against P. aeruginosa (0.0113 µmol/mL), A. niger (0.0113 µmol/mL) and C. albicans (0.0056 µmol/mL) wherein triazolyl imidazoles 3i was found to be more potent against B. subtilis (0.0122 µmol/mL) & A. niger (0.0121 µmol/mL); and compound 3r was also found to be more potent against S. epidermidis (0.0117 µmol/mL) & C. albicans (0.0058 µmol/mL). As a result of docking studies, the binding affinity of the compound 3o was –9.6 kcal/mol which was even more in comparison to the binding affinity of co-crystallized ligand CBN (–9.4 kcal/mol).

Background: High performance hybrid broilers require a high energy diet to exploit their full genetic potential. Therefore, high energy sources are being used in broiler diet which creates interest in the use of emulsifiers along with fat source. Hence, this study was conducted to evolve emulsifier supplementation strategy in low energy diet containing tallow as fat source in commercial broiler chickens. Methods: Total of 150 day old broiler chicks randomly distributed into three treatments with 5 replicates of ten chicks each. Treatment groups were fed basal diet which contains tallow as energy source (T1), basal diet supplemented with emulsifier at 250g per tonne of feed (T2) and 80 kcal Metabolizable energy reduced from basal diet supplemented with emulsifier at the rate of 250g per ton of feed (T3). Result: At 6th week of age significantly highest body weight was noticed in T2 group, lowest feed intake was recorded in T2 group but feed conversion ratio was comparable between T3 (1.72) and T2 (1.74) groups. No significant difference in carcass parameters and serum biochemical parameters were noticed. Emulsifier supplementation with reduced metabolizable energy can be used as a feeding strategy in broiler chickens to improve the production performance.

Cobalt, nickel and copper doped non-stoichiometric CdGa2O4 were synthesized via epoxide gel approach. Cubic spinel arrangement of undoped and doped samples was investigated from powder X-ray diffraction pattern and the complete structure analysis was done by using Raman spectroscopy. Additionally, cubic morphology of doped samples was analysed by FESEM images and elemental ratio of these samples have been obtained using Energy Dispersive spectrum (EDS). The oxidation state of doped metal ions was determined by optical and photoluminescence spectroscopy. The magnetic study of the doped samples showed the antiferromagnetic and ferromagnetic behaviour. The variation of band gap in transition metal doped samples has been favourably utilized for the photodegradation studies of aqueous solution of methylene blue and Rhodamine B dye.

The influence of novel Cd-Ni co-substituted BiFeO3 (BFO) on structural, magnetic, optical and photocatalytic properties of nanoparticles were studied. Samples were prepared using tartaric acid modified sol-gel technique. Doping-induced structural distortion from rhombohedral to orthorhombic phase was confirmed by XRD and Raman results. The crystallite size decreases from 16.49 to 11.23 nm with increasing the dopant concentration. Morphological studies using HR-SEM revealed that the average particle size decreased significantly from 91.90 to 53.52 nm. EDX studies were used to validate the sample elemental analysis. Furthermore, the effective co-substitution of Cd-Ni into the bismuth ferrite lattice improved the saturation magnetization from 0.096 emu/g to 2.420 emu/g. The XPS confirmed the dominance of the Fe3+ oxidation state. The optical bandgap of BFO nanoparticles could be tuned by Cd-Ni co-doping from 2.06 eV to 1.75 eV. Also, Bi1-xCdxFe1-xNixO3 (BCFNO-6) sample demonstrated the best Methylene blue (MB) and Rhodamine B (RhB) degradation activity under UV-visible irradiation.

Bi1-xSmxFeO3 (BSFO, x = 0, 0.05, 0.10, 0.15, 0.20) nanoparticles were prepared through tartaric acid-modified sol-gel technique. X-ray diffraction and scanning electron microscopy provide phase purity and nanocrystalline behavior (29–92) nm of pristine and doped BFO nanoparticles. The crystallite sizes of the studied samples ranged from 19.64 nm to 12.26 nm. The Rietveld refinement of XRD data demonstrated a good configuration of change in the crystalline structure. Structural phase analysis by XRD suggested that structural transformation from rhombohedral structure (R3c space group) to orthorhombic structure (Pnma space group) is observed in Sm substituted BFO nanoparticles. The ferromagnetic properties increase up to x = 15 % in the samples with enhancing magnetization. A large component of the orthorhombic phase for x = 20 % sample results from a drastic decrease in the ferromagnetic property due to collinear antiferromagnetic ordering correlated with VSM and EPR studies.

We report the evolution of structural, physical and magnetic properties of Zr doped Bi0.90Gd0.10Fe1-xZrxO3, (x = 0.0, 0.03, 0.07 and 0.10) nanoparticles prepared by tartaric acid based sol gel route. Rietveld refinement of X-ray diffraction patterns shows the coexistence of rhombohedral (R3c) and orthorhombic (Pbnm) phase in all the samples. Morphological studies confirm the compositional driven reduction in particle size with increasing Zr concentration due to filling of oxygen vacancies and hence lower grain growth. The magnetic measurements at room temperature indicate that Zr substitution induces weak ferromagnetism and discerns large and non-zero remanant magnetization. Both dielectric constant (e′) and loss factor (tan δ) of these samples decrease with increasing Zr concentration, indicating improved dielectric properties due to the suppression of oxygen vacancies in co-doped compositions. An anomaly in dielectric constant and dielectric loss is observed in the vicinity of antiferromagnetic Neel temperature. Fourier transform infrared spectra show that the Fe–O bond length decreases with increasing Zr concentration which is consistent with the Rietveld analysis. The UV–visible diffuse reflectance spectroscopy measurements show a significant reduction in the optical band gap value from 2.35 eV to 2.05 eV for Bi0.90Gd0.10Fe1-xZrxO3 samples.

In this study BiFeO3 (BFO), Bi0.9Dy0.1FeO3 (BDFO) and Bi0.9Dy0.1Fe0.97Zr0.03O3 (BDFZO) nanoparticles were prepared by sol-gel route. X-ray diffraction study showed rhombohedral structure for BFO while orthorhombic structure for BDFO and BDFZO samples. X-ray photoelectron spectroscopy indicated the dominancy of Fe3+ oxidation state in BDFO sample which decreases in BDFZO sample. All samples showed ferromagnetic behaviour with saturation magnetization of 0.5, 5.5 and 5.2 emu/g for BFO, BDFO and BDFZO samples, respectively. A slight decrease in magnetization for BDFZO sample as compared to BDFO sample may be attributed to the substitution of non-magnetic Zr4+ ion which does not take part directly in magnetization. Two-phonon Raman mode located at ∼1260 cm−1 showed anomalous intensity in pure BFO which subsequently suppressed for BDFO and BDFZO samples indicating spin-two phonon coupling in these samples. UV–Visible diffuse spectroscopy results showed that the band-gap of BFO, BDFO and BDFZO samples were 2.26, 2.22 and 2.24 eV, respectively, suitable for photocatalytic applications.

Background: Most surgeries are carried out with ease using neuromuscular blocking agents. This study was aimed to compare the intubating dose of cisatracurium and rocuronium regarding the onset of action, clinical duration, recovery index, intubating conditions, efficacy, and safety in elective surgery. Method: 60 adult patients of American Society Anesthesiology (ASA) grade I & II, underwent elective laparoscopic surgery were randomized to receive either cisatracurium 0.1 mg/kg (Group C) or rocuronium 0.6 mg/kg (Group R). Neuromuscular monitoring was done using STIMPOD Xavant NMS450. Relaxogram interpretation was carried out for the onset of action, clinical duration, and recovery index. Results: Cisatracurium had significant longer onset (233.33±62.31 vs. 86.66±28.62 seconds, p

The effect of Na and Co co-substitution is explored on structural, magnetic and photocatalytic properties of Bi1-xNaxFe1-xCoxO3 (x = 0.00–0.08) nanoparticles, synthesized via the tartaric acid based wet chemical sol–gel technique. X-ray diffraction along with the electron microscopy techniques disclosed the pure phase and nanocrystalline nature of Bi1-xNaxFe1-xCoxO3 samples. The ferromagnetic ordering parameters increase with increasing Na–Co content in BiFeO3 nanoparticles and the highest magnetization 2.84 emu/g at 30 kOe is observed for x = 0.08 sample which is also endorsed by the ESR analysis. The Raman study supported the magnetic properties of Bi1-xNaxFe1-xCoxO3 nanoparticles. XPS measurements of the Bi1-xNaxFe1-xCoxO3 nanoparticles showed the Fe3+ dominancy and increase in oxygen vacancies with Na–Co content. The energy band-gap of BiFeO3 nanoparticles can be altered by aliovalent ions Na–Co substitution from 2.2 eV to 1.97 eV. The co-doping has improved the photodegradation efficiency and kinetic degradation rates of methylene blue and crystal violet under UV light irradiation.

The manifestation of dimensionalities and SiO 2 shell induced modifications in structural, vibrational, dielectric and magnetic properties of microcrystalline, nanocrystalline BiFeO 3 and core–shell structured BiFeO 3 @SiO 2 nanoparticles are reported. Transmission electron microscopy image confirmed the core–shell structure of BiFeO 3 @SiO 2 nanoparticles with BiFeO 3 core ∼50–90 nm and SiO 2 shell ∼16 nm. X-ray diffraction and Raman spectroscopy results show the presence of distorted rhombohedral structure with R3c space group in all samples. Bond valance sum (BVS) calculations shows the SiO 2 shell includes very small compressive stress of Bi–O and increases tensile stress of the Fe–O bonds in comparison with BiFeO 3 nanoparticles. SiO 2 shell on BiFeO 3 nanoparticles reduces the dielectric constant and loss in comparison with microcrystalline and nanocrystalline BiFeO 3 samples. The magnetic measurement indicated the existence of room-temperature weak ferromagnetism in BiFeO 3 and core–shell BiFeO 3 @SiO 2 nanoparticles, whereas bulk BiFeO 3 showed antiferromagnetic nature (almost paramagnetic in nature), which is also endorsed by second order Raman modes. The influence of the grain boundary specific area (S GB ) on ferromagnetism in microcrystalline and nanocrystalline BiFeO 3 samples has been deciphered.

The manifestation of dimensionalities and Sr induced modifications in structural, vibrational and magnetic properties of Bi1−xSrxFeO3; (x = 0–0.25) nanoparticles synthesized by a tartaric acid based sol–gel route are reported. X-ray diffraction and electron microscopy studies reveal the phase purity and nanocrystalline nature (45–90 nm) of Bi1−xSrxFeO3 samples. The Sr ions substitution motivated the coexistance of rhombohedral (R3c) and pseudo tetragonal (P4/mmm) structural symmetry for the x = 0.25 sample which leads to enhancement of saturation magnetization due to the distorted cycloid spin structure and uncompensated surface spins, which is in concomitance with the electron paramagnetic resonance (EPR) and Mossbauer studies. The ferromagnetic ordering contribution continuously increases with increasing Sr content from x = 0–0.25 samples with a maximum saturation magnetization of 0.72 emu g−1 for the x = 0.25 sample which is also endorsed by second order Raman modes. X-ray photoelectron and Mossbauer measurements confirmed the dominance of the Fe3+ oxidation state. Alteration in QS hyperfine parameters and line-width analysis have been probed by Mossbauer analysis with increasing Sr content in BiFeO3 nanoparticles suggesting the destruction of the spin cycloid.

Bi1−xCaxFeO3; (x = 0–0.20) nanoparticles were synthesized by tartaric acid based sol–gel route. X-ray diffraction and electron microscopy studies reveal the phase purity and nanocrystalline nature (45–90 nm) of Bi1−xCaxFeO3 samples. The Ca ion substitution driven structural transition from rhombohedral (space group R3c) to orthorhombic (Pnma) symmetry leads to enhancement in saturation magnetization due to the distorted cycloid spin structure (as also suggested by Mossbauer studies) and uncompensated surface spins which is accorded with electron paramagnetic resonance (EPR) studies as well. The ferromagnetic ordering contribution increases up to x = 0.15 samples with maximum saturation magnetization of 0.09 emu g−1 for x = 0.15 sample. The presence of high content orthorhombic phase for x = 0.20 sample results in the sharp decrease in the ferromagnetic component due to appearance of collinear antiferromagnetic ordering in agreement with EPR results. X-ray photoelectron spectroscopy confirmed the dominancy of Fe3+ oxidation states along with the shifting of the binding energy of Bi 4f orbital indicating the substitution of Ca2+ at Bi-site. Systematic change of Mossbauer parameters of nanoparticulate samples with Ca concentration are obtained by Mossbauer spectroscopy. The results of both one- and two-sextet fittings of the Mossbauer spectra provide evidence for destruction of the spin cycloid in Ca-doped BiFeO3 nanoparticles.

Phase pure Bi1-xPbxFeO3 ceramics with x = 0.0, 0.05, 0.15 and 0.25 were prepared by rapid liquid phase sintering process. Impact of Pb+2 substitutions on structural and multiferroic properties was studied. The formation of the desired phase was examined by X-ray diffraction. A spontaneous polarization (PS) of 18 µC/cm2 and remanent polarization (Pr) of 6.9 µC/cm2 were measured for x = 0.25 sample with applied electric field of 37 kV/cm. The M-H hysteresis loops exhibited antiferromagnetic nature with weak ferromagnetism and the enhancement in magnetization with increasing Pb+2 contents. The magnetization first decreases with the decrease in temperature up to 115 K, and then increases rapidly as temperature further decreases up to 5 K for x = 0.25 sample. The maximum spontaneous magnetization of 0.97 emu/g was observed for x = 0.25 sample at 5 K.

Bi1-xCaxFe1-xNixO3 nanoparticles with x = 0.0, 0.05, 0.10 and 0.15 were effectively synthesized using a profitable route, tartaric acid based sol-gel one. In BiFeO3 at Bi and Fe-sites, the co-substitution of alkali earth metal Ca2+ ions and transition metal Ni2+ ions leads to structural distortion, reduction in average grain size and enhanced magnetic properties. The study of XRD and Raman scattering demonstrated the compressive lattice distortion in the samples occurred from the co-substitution of Ca2+ and Ni2+ ions. The measurements of XRD patterns and Raman spectroscopy also recommended the coexistence of rhombohedral and orthorhombic phases in co-substituting BiFeO3 samples. Room temperature enhanced ferromagnetic behavior demonstrated with magnetic study, by the co-substitution of Ca2+ and Ni2+ ions at Bi and Fe-site, respectively. The line shape of electron paramagnetic resonance spectra changes continuously due to the local distortion caused from substituting Ni.

Bi1-xCaxFe1-xCoxO3 nanoparticles with x=0.0, 0.05, 0.10 and 0.15 were successfully synthesized by cost effective tartaric acid based sol gel route. The alkali earth metal Ca2+ ions and transition metal Co3+ ions codoping at A and B-sites of BiFeO3 results in structural distortion and phase transformation. Rietveld refinement of XRD patterns suggested the coexistence of rhombohedral and orthorhombic phases in codoped BiFeO3 samples. Both XRD and Raman scattering studies showed the compressive lattice distortion in the samples induced by codoping of Ca2+ and Co3+ ions. Two-phonon Raman spectra exhibited the improvement of magnetization in these samples. X-ray photoelectron spectroscopy (XPS) showed the dominancy of Fe3+ and Co3+ oxidation states along with the shifting of the binding energy of Bi 4f orbital which confirms the substitution Ca2+ at Bi-site. The magnetic study showed the enhancement in room temperature ferromagnetic behavior with co-substitution consistent with Rama analysis. The gradual change in line shape of electron spin resonance spectra indicated the local distortion induced by codoping. (C) 2015 Published by Elsevier Ltd and Techna Group S.r.l.

Structural, magnetic and optical properties of Bi 0.85 Ho 0.15 Fe 1− x Co x O 3 ( x =0.0–0.15) nanoparticles have been studied. X-ray diffraction patterns and Raman spectra demonstrate orthorhombic structure for all samples. Spontaneous magnetization of Ho–Co co-substituted BiFeO 3 nanoparticles increased up to 3.71 emu/g for x =0.15. Electron spin resonance analysis showed that the addition of Co 2+ ions is likely to increase the spin canting angle and reduces anisotropy which favors the enhanced ferromagnetism. Optical studies in the spectral range from 1.1 to 5 eV showed two d–d crystal field transitions and three charge–transfer transitions with band gap variation from 2.60 to 2.38 eV.

Rare earth Dy substituted BiFeO3 (Bi1 � xDyxFeO3) nanoparticles with x ¼0.03, 0.05 and 0.10 were prepared by a sol–gel method. Rietveld analysis of the X-ray diffraction patterns and Raman spectroscopy confirmed substitution induced phase transformation from rhombohedral to orthorhombic phase for x ¼0.10. In Raman spectra, the broad band ranging from 900 to 1400 cm � 1 , associated with strong spin-two phonon coupling behavior, was observed. Magnetic studies showed enhancement in magnetization in which the saturation magnetization of 5.5 emu/g for x ¼0.10 sample has been measured. Dielectric measurements showed magnetoelectric coupling around Neel temperature in all the samples. Conductivity of the samples decreases with increasing Dy concentration, indicating suppression of oxygen vacancies. The change in Bi–O and Fe–O bond lengths with increasing Dy content observed from infrared spectroscopy analysis is also found to be in agreement with Rietveld refinement results. & 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Single-phase (Bi 1− x Pr x )(Fe 1− x Ti x )O 3 ceramics ( x =0.03, 0.06, and 0.10 as BPFT-3, BPFT-6 and BPFT-10, respectively) were synthesized by conventional solid state reaction method. The effect of varying Pr and Ti codoping concentration on the structural, magnetic, dielectric and optical properties of the BPFT ceramics have been investigated. X-ray diffraction indicated pure rhombohedral phase formation for BPFT-3 and BPFT-6 ceramics, however, a structural phase transition from a rhombohedral to an orthorhombic phase has been observed for BPFT-10 ceramic. The maximum remnant magnetization of 0.1824 emu/g has been observed in BPFT-6. With increasing codoping concentration the room temperature dielectric measurements showed enhancement in dielectric properties with reduced dielectric loss. UV–vis diffuse reflectance spectra demonstrated the strong absorption of light in the visible region for a band gap variation 2.31–2.34 eV. Infrared spectroscopy indicated the shifting of Bi/Pr–O and Fe/Ti–O bonds vibrations and change in Fe/Ti–O bond lengths. Decrease in the conductivity on increasing Pr and Ti concentration in BFO is attributed to an enhancement in the barrier properties leading to suppression of lattice conduction path arising due to lattice distortion as confirmed from impedance analysis.

Non-magnetic Zr4+ ions substituted BiFeO3 nanoparticles (BiFe1−x Zr x O 3, x = 0.0, 0.03 and 0.10) were synthesized by sol-gel method. X-ray diffraction and Raman studies indicate the rhombohedral phase for all the samples. The particle size decreases with increasing Zr4+ concentration and varies in the range 20–50 nm. The absorption spectra show the strong absorption of visible light with optical band gap variation 2.27–2.21 eV for pure and Zr-doped BFO nanoparticles. A large saturation magnetization value of 9.33 emu/g is observed for x = 0.03 sample. The reduction in saturation magnetization for x = 0.10 sample is attributed to the dominant role of an increasing number of non-magnetically active Zr4+ ions, and the formation of Fe–O–Zr coordination with increasing Zr4+ ions concentration becomes less magnetic sublattice.

Bi1−xDyxFeO3 (x=0.0, 0.03, 0.05, 0.07, 0.10 and 0.12) ceramics were synthesized by solid state reaction method. Effects of Dy substitution on structural distortion, magnetic and optical properties of BiFeO3 were examined by X-ray diffraction, Raman and UV–Visible spectroscopy. The samples were found to crystallize in rhombohedral structure of BiFeO3 with R3c space group. The reduction in lattice parameters and unit cell volume indicate the distortion in FeO6 octahedra of the rhombohedral structure without any signature of phase transformation up to x=0.12. The predictable weak ferromagnetic hysteresis loops can be observed in the Dy doped samples with maximum remnant magnetization of 0.2103 emu/g for x=0.12. The weak ferromagnetism is ascribed to the suppressed spiral spin structure and magnetically active characteristic of Dy3+ ions together with ferromagnetic coupling between Dy3+ and Fe3+ ions. With optical band gap in visible region, Dy doped BiFeO3 ceramics are potential material for optoelectronic device and solar cell applications.

Ca and Ca–Li substitution dependent modification in structural, electron density, vibrational, magnetic and optical properties of BiFeO3 nanoparticles synthesized by tartaric acid based sol–gel route are reported. X-ray diffraction and transmission electron microscopy techniques revealed the phase purity and nanocrystalline nature of BiFeO3, Bi0·95Ca0·05FeO3, Bi0·95Ca0·05Fe0·95Li0·05O3 samples. The electron density plots indicated the displacement of Bi and Fe ions and partial covalency of Bi–O and Fe–O the bonds. The Ca and Ca–Li ions substitution induced distortion in rhombohedral structure resulting in enhanced magnetization of BiFeO3 nanoparticles. The magnetization is highest for Ca–Li substituted BiFeO3 nanoparticles with saturation magnetization of 0.036 emu/g due to the canted spin structure and uncompensated surface spins. The enhanced magnetic properties are also endorsed by the electron spin resonance and Raman studies. The band-gap of BiFeO3 nanoparticles can be tuned by aliovalent ions substitution from 2.26 eV for BiFeO3 to 2.20 and 2.17 eV for Ca, and Ca–Li substituted BiFeO3 nanoparticles respectively.