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Chromium (Cr)-doped cobalt ferrite nanoparticles were synthesized using a sol–gel autocombustion method, with the chemical formula CoCrxFe2xO4. The value of x ranged from 0.00 to 0.5 in 0.1 increments. X-ray diffraction analysis confirmed the development of highly crystalline cubic spinel structures for all samples, with an average crystallite size of approximately 40 to 45 nm determined using the Scherrer equation. Pellets were prepared using a traditional ceramic method. The magnetic and magnetostrictive properties of the samples were tested using strain gauge and VSM (vibrating sample magnetometer) techniques. The results of the magnetic and magnetostrictive tests showed that the chromium-substituted cobalt ferrites exhibited higher strain derivative magnitudes than pure cobalt ferrite. These findings indicated that the introduction of chromium into the cobalt ferrite structure led to changes in the material's magnetic properties. These changes were attributed to anisotropic contributions, resulting from an increased presence of Co2+ ions at B-sites due to the chromium substitutions. In summary, this study concluded that introducing chromium into the cobalt ferrite structure caused alterations in the material's magnetic properties, which were explained by changes in the cationic arrangement within the crystal lattice. This study successfully explained these alterations using magnetization and coercivity data and the probable cationic dispersion. [ABSTRACT FROM AUTHOR]

The SiO2 glasses embedded with Cr3+ ions are notable for solid state optical resource, which are useful in various opto-electronic and semiconducting applications. However, the available thermoluminescent resource, which include different electronic and semiconducting materials, need some refinement in their structure, luminescence, and electronic properties towards development of advanced glass resource. In this vision, CrxCa(10-x)Al30Si60 glassy materials have planned for synthesis and testing. The GT, and GC phase transition points, and thermal stability (~1.2639) of test samples are identified. Structural vibrations are identified with the help of FT-IR spectra. The order of electrical conductivity (~1.657x10-4 ohm-1 cm-1), and A.E. (~0.3669 eV) of test samples reveal their electrical strength. The symmetry (~ 0.576%) factor, frequency (1.1172 X 1020 S-1) factor, and A.E. (0.682 eV) of the test samples are recorded under 30 kGy irradiation. Overall, the results, which include structure, electrical and luminescence of the test samples suggest the materials might be useful electrically conductive and thermal stimulated light resource. [ABSTRACT FROM AUTHOR]

The paper presents the effect of electron beam (EB) irradiation on poly (L-Lactic acid) (PLLA). The resultant physicochemical properties were investigated using Electron spin resonance spectrometer (ESR), Fourier transform infrared spectrometer (FTIR), Differential scanning calorimetry (DSC), X-ray Diffraction (XRD) and Scanning electron microscopy (SEM). The results suggest that PLLA undergoes random chain scission producing two types of free radicals ~Ċ(CH3)~ (I) and ĊH(CH3)~ (II) at room temperature. Presence of these free radicals has been confirmed by the ESR method and computer simulation studies using easyspin tool. FTIR results depict that the intensity of the absorption band 1745 cm-1 is reduced by 12% for 90 kGy dose. DSC studies indicate that both glass transition temperature (Tg) and melting temperature (Tm) of PLLA decrease following radiation dose. However melting enthalpy (ΔH) and degree of crystallinity (XC) increased initially up to 30 kGy of radiation dose followed by a decrease after 30 kGy. These results confirm the existence of two types of crystalline lamellar are present in PLLA. Measurements of XC by XRD also confirm the same aspect. The surface of PLLA is composed of micro-cracks when exposed to higher radiation doses. [ABSTRACT FROM AUTHOR]

CaxBa1-xNb2O6 (CBN) ceramics with tetragonal tungsten bronze (TTB) structures are very attractive from academic and technological fronts due to their stupendous ferroelectric properties. Polycrystalline samples of CaxBa1-xNb2O5 were prepared by a high temperature solid state reaction technique. The phase formation, microstructure and optical properties of the prepared samples were investigated by X-ray diffraction, scanning electron microscope and Raman spectrometer, respectively. X-ray analysis confirms the partially filled tetragonal tungsten bronze (TTB) structure. Scanning electron micrographs provide information related to the morphology and grain size distribution of the samples. Detailed analysis of the structural and optical properties suggests that these samples have undergone a phase transition well above the room temperature. [ABSTRACT FROM AUTHOR]

Fast ion-conducting (FIC) system composed of xCdI2-(100-x)[44.4Ag2SO4-55.6(40TeO2-60B2O3)] has been prepared by melt-quenching method. The prepared samples were characterized by X-ray diffraction (XRD), impedance, and transport studies. XRD, DSC studies conclude that the samples with x = 0 to 20 show predominantly glassy nature. Conductivity measurements were performed in the frequency range 20 Hz-3 MHz by varying temperature from 30 to 150 °C. Electrical parameters such as conductivity and activation energies of all the samples were evaluated by complex impedance analysis and Arrhenius plots, respectively. The obtained results of conductivity are discussed using exchange reaction between the cations based on Lewis’ hard and soft acids and bases (HSAB) principle. Ionic conductivity is identified as being mainly due to Ag+ ions. The highest conductivity (order of 10−4 S cm−1) and ionic current (2.063 μA) is observed for CBT20 sample at room temperature; hence, it can be used as the best electrolyte material for solid-state battery application. [ABSTRACT FROM AUTHOR]

Mn substituted Ni-Zn ferrite nanoparticles, Ni 0.4 Zn 0.6- x Mn x Fe 2 O 4 ( x  = 0.00–0.25 in steps of 0.05), using metal nitrates were prepared by sol-gel autocombustion in citric acid matrix. The samples were examined by X-ray diffraction and vibrating sample magnetometer techniques. Rietveld structural refinements using the XRD data were performed on the samples to consolidate various structural parameters like phase (spinel), crystallite size (24.86–37.43 nm), lattice constant (8.3764–8.4089 Å) etc and also to determine cation distributions based on profile matching and integrated intensity ratios. Saturation magnetization values (37.18–68.40 emu/g) were extracted from the measured M−H loops of these nanoparticles to estimate their magnetic moments. Experimental and calculated magnetic moments and lattice constants were used to confirm the derived cation distributions from Rietveld analysis. The results of these ferrite nanoparticles are discussed in terms of the compositional modifications, particle sizes and the corresponding cation distributions as a result of Mn substitutions. [ABSTRACT FROM AUTHOR]

Fast ion conducting (FIC) glasses of composition 60%AgI-[MAg2O-F{(F1)B2O3-(F2)TeO2}] (SBT2);where M/F = 0-2 in steps of 0.25 for a fixed values of former [F={(F1 = 0.4)+(F2 = 0.6)}]are prepared by melt quenching technique. X-ray diffraction and differential scanning calorimetry studies were carried out understand some structural aspects of the glasses. With increasing the value of M/F ratio upto 1.50 (SBT2-6), the samples exhibited amorphous nature and for further increase of this ratio, crystallinity could be visualized. The electrical properties of these glasses are investigated by impedance spectroscopy in the frequency range 1 kHz-3 MHz and also DC conductivity in the temperature range 303-423 K. The conductivity is observed to increase while the activation energy exhibited decreasing trend with increase of modifier (Ag2O) concentration upto M/F = 1.50. The electrical properties of these glass systems were described as a parallel RC circuit in which R represents the bulk resistance (Rb) and C represents the bulk capacitance (Cb) of the sample. The AC conductivity is also found to increase upto M/F = 1.50. The glasses exhibited high ionic conductivity and near unity ionic transport number, such observation confirms the studied materials are superionic conductors. Overall analysis of the results further indicated the SBT2-6 sample (which is amorphous in nature) that exhibited the highest conductivity with lowest activation energy and high ionic transport number is better useful as solid electrolyte (SE) in solid state batteries (SSBs). [ABSTRACT FROM AUTHOR]

Double perovskite oxide Ba2CeZrO6 is synthesized by sol–gel technique for the first time. The X-ray diffraction pattern at room temperature show that the sample exists in single phase and crystallizes in cubic structure with space groupFm3-m. The lattice parameter is found to be 0.8635 nm. A scanning electron micrograph image of the Ba2CeZrO6 sample show uniform distribution of grains size ranging from 2.4 to 3 μm. EDAX spectra showed that Ba2CeZrO6 sample contains only Ba, Ce, Zr and O elements which are closer to stoichiometric ratio. Fourier transform infrared spectra of Ba2CeZrO6 showed the peaks observed corresponds to CeO6 and ZrO6 octahedra indicates the formation of double perovskite structure. The tolerance factor (t) of Ba2CeZrO6 sample is 0.90 suggests unit cell has a small distortion from ideal cubic structure. Frequency (100 Hz–5 MHz) dependent impedance spectroscopy studies were carried out at different temperatures ranging from room temperature to 400 °C. The decrease in impedance (Z), relaxation time (τ) and grain, grain boundary resistance and increase in conductivity with increase in temperature shows the semiconducting nature of the Ba2CeZrO6 sample. Nyquist analysis showed the contribution of grain and grain boundary resistances for the relaxation process in Ba2CeZrO6 sample. The relaxation mechanism in the sample is found to be independent of temperature. The activation energy of Ba2CeZrO6 sample is found to be 0.38 eV. [ABSTRACT FROM AUTHOR]

In the present work, well-dispersed gold nanoparticles (AuNPs) were synthesised by the reduction of HAuClxHO using silk fibroin as a reducing agent. UV-visible spectroscopy confirmed the formation of AuNPs by showing surface plasmon resonance (SPR) at 526-518 nm. The FT-IR study revealed that the hydroxyl groups in the Tyr residue and the carboxyl groups in the Asp and/or Glu residues were the most active functional groups for the conversion of Au ion reduction. The transmission electron microscope (TEM) images showed that the formed nanoparticles were uniformly embedded in the silk fibroin solution. The AuNPs are spherical in shape with smooth edges and around 5-8 nm in diameter. Also, these possess very good stability and dispersity and can be stored for a long period. Further, the X-ray diffraction (XRD) study confirmed the nanocrystalline phase of the gold with cubic crystal structure. The biogenic gold nanoparticles displayed antibacterial activity against Gram-positive and Gram-negative bacteria, and also showed promising anticancer properties. [ABSTRACT FROM AUTHOR]

The aging behavior of precipitation hardenable 17-4 PH stainless steel is studied by analyzing the changes in microstrain, crystallite size, and dislocation density derived from the modified Williamson--Hall (mWH) method and the Fourier analysis of XRD profiles. Aging treatment of this steel at 380, 430, and 480 °C for 0.5, 1, and 3 h durations leads to changes in the microstrain due to precipitation and substructural changes caused by dislocation annihilation. The microstrain estimated from the mWH method is dominated by the precipitate-induced effects. The influence of precipitates and dislocations on the mean squared strain <ε²(L)> are separated by fitting the variation of <ε²(L)> with an expression P0 + P1/L + P2/L², where the parameter (P0)0.5 and P1 are shown to be related to the precipitate-induced and dislocation density-induced microstrain, respectively. The study shows that the XRD profile analysis can be used to separate the combined effects of precipitation and dislocation annihilation. [ABSTRACT FROM AUTHOR]

Nanocrystalline mesoporous spinel magnesium ferrite (MgFe 2 O 4 ) particles with high surface area were prepared by urea assisted modified citrate combustion process. The prepared sample was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, field-emission scanning electron microscope (FE-SEM), BET surface area analyzer and impedance spectroscopy techniques. XRD results confirmed the formation of a single phase of nanocrystalline spinel magnesium ferrite sample. FTIR and Raman spectroscopy (FTIR) results confirmed the structural co-ordination of the magnesium ferrite sample. The spherical shape morphology of the prepared magnesium ferrite particles was confirmed from the FE-SEM images. Specific surface area and porosity of the MgFe 2 O 4 sample were obtained from N 2 adsorption–desorption isotherms results. The D.C. and A.C. electrical conductivities of the MgFe 2 O 4 sample as a function of temperature and frequency were investigated by analyzing the measured impedance data. The activation energy for the migration of the carriers in the MgFe 2 O 4 sample was found to be 0.607 eV. The dielectric studies revealed that the dielectric constant of the mesoporous MgFe 2 O 4 sample increases with increase in temperature. Further, lithium battery was fabricated using the developed nanocrystalline mesoporous spinel MgFe 2 O 4 as anode material and investigated its electrochemical performance. The charge-discharge studies revealed that the fabricated lithium battery using the developed nanocrystalline mesoporous MgFe 2 O 4 as anode exhibited high capacity and good cycleability in the voltage range 0.005–3 V. The results show that the developed nanocrystalline mesoporous spinel magnesium ferrite could be a better anode material for lithium battery applications. [ABSTRACT FROM AUTHOR]

17-4 PH (precipitation hardening) stainless steel is a soft martensitic stainless steel strengthened by aging at appropriate temperature for sufficient duration. Precipitation of copper particles in the martensitic matrix during aging causes coherency strains which improves the mechanical properties, namely hardness and strength of the matrix. The contributions to X-ray diffraction (XRD) profile broadening due to coherency strains caused by precipitation and crystallite size changes due to aging are separated and quantified using the modified Williamson-Hall approach. The estimated normalized mean square strain and crystallite size are used to explain the observed changes in hardness. Microstructural changes observed in secondary electron images are in qualitative agreement with crystallite size changes estimated from XRD profile analysis. The precipitation kinetics in the age-hardening regime and overaged regime are studied from hardness changes and they follow the Avrami kinetics and Wilson's model, respectively. In overaged condition, the hardness changes are linearly correlated to the tempering parameter (also known as Larson-Miller parameter). Similar linear variation is observed between the normalized mean square strain (determined from XRD line profile analysis) and the tempering parameter, in the incoherent regime which is beyond peak microstrain conditions. [ABSTRACT FROM AUTHOR]

Ultrasonic measurements have been carried out in Ti-10V-4.5Fe-1.5Al β-titanium alloy specimens subjected to β annealing at 1173 K (900 °C) for 1 hour followed by heat treatment in the temperature range of 823 K to 1173 K (550 °C to 900 °C) at an interval of 50 K (50 °C) for 1 hour, followed by water quenching. Ultrasonic parameters such as ultrasonic longitudinal wave velocity, ultrasonic shear wave velocity, shear anisotropy parameter, ultrasonic attenuation, and normalized nonlinear ultrasonic parameter have been correlated with various microstructural changes to understand the interaction of the propagating ultrasonic wave with microstructural features in the alloy. Simulation studies using JMatPro software and X-ray diffraction measurements have been carried out to estimate the α-phase volume fraction in the specimens heat treated below the β-transus temperature (BTT). It is found that the α-phase (HCP) volume fraction increases from 0 to 52 pct, with decrease in the temperature from 1073 K to 823 K (800 °C to 550 °C). Ultrasonic longitudinal and shear wave velocities are found to increase with decrease in the heat treatment temperature below the BTT, and they exhibited linear relationships with the α-phase volume fraction. Thickness-independent ultrasonic parameters, Poisson's ratio, and the shear anisotropy parameter exhibited the opposite behavior, i.e., decrease with increase in the α-phase consequent to decrease in the heat treatment temperature from 1073 K to 823 K (800 °C to 550 °C). Ultrasonic attenuation is found to decrease from 0.7 dB/mm for the β-annealed specimen to 0.23 dB/mm in the specimen heat treated at 823 K (550 °C) due to the combined effect of the decrease in the β-phase (BCC) with higher damping characteristics and the reduction in scattering due to randomization of β grains with the precipitation of α-phase. Normalized nonlinear ultrasonic parameter is found to increase with increase in the α-phase volume fraction due to increased interfacial strain. For the first time, quantitative correlations established between various ultrasonic parameters and the volume fraction of α-phase in a β-titanium alloy are reported in the present paper. The established correlations are useful for estimation of volume fraction of α-phase in heat-treated β-titanium alloy, by nondestructive ultrasonic measurements. [ABSTRACT FROM AUTHOR]

Alkaline earth lead zinc phosphate glasses doped with Mn(II) are characterized by spectroscopic techniques like X-ray diffraction (XRD), UV-visible, differential scanning calorimetry (DSC), electron paramagnetic resonance (EPR), Fourier transform infrared (FTIR) and Raman. Optical absorption spectrum exhibits four bands which are characteristic of Mn(II) in distorted octahedral site symmetry. The crystal field parameter Dq and Racah interelectronic-repulsion parameters B and C have been evaluated. All investigated samples exhibit EPR signals which are characteristic to the Mn ions. The shapes of spectra are also changed with varying alkaline earth ions content. FTIR spectra show specific vibrations of phosphate units. The characteristic Raman bands of these glasses due to stretching and bending vibrations were identified and analysed by varying alkaline earth content. The intensity and frequency variations for the characteristic phosphate group vibrations have been correlated with the changes of the structural units present in these glasses. Depolymerization of the phosphate chains in all the glasses is observed with replacement of alkaline earth content by spectroscopic studies. This leads to a strong decrease of the average chain length and a small decrease of the average P-O-P bridging angle with replacement of alkaline earth content. [ABSTRACT FROM AUTHOR]

The purpose of this study was to develop floating microparticles containing Pioglitazone HCl, for controlled release and perform pharmacodynamic studies. The FTIR and DSC studies revealed that there is no interaction between drug and excipients used. The 22 factorial design was employed to evaluate the effect of drug: polymer (total) and Eudragit RS 100: Eudragit RL 100. The floating microparticles were prepared by solvent evaporation technique. The predicted and actual values of drug release at 1 h, 8 h and drug entrapment were 38.307%, 77.76%, 84.25% and 38.712%, 76.237% and 84.62%, respectively. XRD and SEM studies showed reduced crystallinity of drug and spherical microparticles. Buoyancy studies revealed good floating of particles for 12 h. Pharmacodynamic studies showed significant reduction in blood glucose levels in male New Zealand rabbits. The results demonstrate the feasibility of the factorial design in successfully developing floating microparticles of Pioglitazone HCl for controlled release. [ABSTRACT FROM AUTHOR]

Abstract: In this paper spectroscopic investigation of Cu2+ doped alkaline earth lead zinc phosphate glasses was done through the spectroscopic techniques like X-ray diffraction, Ultra Violet (UV) absorption Spectroscopy, Electron Paramagnetic Resonance (EPR – X band), Fourier Transform Infra Red (FTIR) and Raman Spectroscopy. Alkaline earth lead zinc phosphate glasses containing 0.1% copper oxide (CuO) were prepared by the melt quenching technique. Spectroscopic studies indicated that there is a greater possibility for the copper ions to exist in Cu2+ state in these glasses. The optical absorption spectra indicated that the absorption peak of Cu2+ is a function of composition. The maxima absorption peak was reported at 862nm for strontium lead zinc phosphate glass. Bonding parameters were calculated for the optical and EPR data. All these spectral results indicated clearly that there are certain structural changes in the present glass system with different alkaline earth contents. The IR and Raman spectra noticed the breaking of the P–O–P bonds and creating more number of new P–O–Cu bonds. [Copyright &y& Elsevier]

The plant fibers are rich in cellulose and they are easily renewable source of fibers with the potential for polymer reinforcement. The presence of surface impurities and the large amount of hydroxyl groups make plant fibers less attractive for reinforcement of polymeric materials. Hemp (Cannabis sativaL.) fibers were subjected to alkalization using 1N sodium hydroxide (NaOH). The physical, chemical, and surface properties of untreated and chemically modified fibers are studied using X-ray diffraction (wide angle X-ray scattering), Fourier transform infrared spectroscopy and scanning electron microscopy (SEM), respectively. The microstructural parameters such as crystallite size 〈N〉, lattice strain (gin %), and enthalpy (α*) have been determined by X-ray line profile analysis using Fourier method of Warren. It was found that the crystallite size 〈N〉 decreases with the increase in treatment time. SEM study shows the fibers surface becoming rough and suitable for reinforcement. [ABSTRACT FROM PUBLISHER]

Abstract: Photoluminescence (PL) of the Sr2CeO4 phosphor, doped with Erbium with different concentrations (0.01, 0.1, 0.5 and 1mol %) is described in the present paper. The phosphors were synthesized using the standard solid state reaction technique using urea and citric acid as fluxes. The prepared phosphors are characterized using X-ray diffraction (XRD), and SEM. PL emission of undoped Sr2CeO4 phosphor and doped with various concentrations of Er was studied. The observed PL emission is at 470nm followed by the primary Er emissions with good intensity at 527, 536, 550, 559 and 567nm. The present phosphor may be a good candidate for compact fluorescent lamps for green emission. [Copyright &y& Elsevier]

In the present work, conventional chemical co-precipitation method was employed for the preparation of CdS nanoparticles. XRD studies reveal that CdS crystallizes in single phase hexagonal structure. The particle size of CdS nanoparticles is obtained as 13nm. Microstructural analysis using Scanning Electron Microscope (SEM) supplemented with EDAX were carried out for the sample to find grain size as well as chemical composition. SEM study reveals that the sample consist of nanoclusters, the grains have aggregated to form clusters. A detailed systematic study on CdS sample is done by characterizing TEM, UV-VIS-NIR spectra, Photoluminescence (PL) spectra, DSC/TGA and FTIR. [ABSTRACT FROM AUTHOR]

Abstract: A new approach based on nonlinear ultrasonic (NLU) technique is presented for nondestructive evaluation of yield strength and tensile strength of cold worked AISI type 304 stainless steel (SS). In this approach, the ultrasonic harmonics generated in cold worked stainless steel, as a result of interaction of ultrasonic wave with dislocations and substructural changes, are measured precisely and the nonlinear ultrasonic parameter, β is determined. A quadratic relationship, with a correlation coefficient better than 0.99, is found between the yield strength and the β parameter as well as between the tensile strength and β parameter of the cold worked specimens. The observed behavior is explained based on microscopy, variations in martensite volume fraction and dislocation density determined from X-ray diffraction profile analysis. The proposed approach can be effectively used for nondestructively ensuring the uniformity of tensile properties of steel components on shop-floor during various stages of manufacturing and also as feedback module in intelligent processing of materials concept. [ABSTRACT FROM AUTHOR]

In the present work, conventional chemical co-precipitation method was employed for the prepation of Nickel (2,4,6,8&10 at % of Ni) doped CdS nanoparticles. The particle size and lattice parameters for each sample are determined from X-ray diffraction (XRD) analysis. From XRD patterns the broadening of the diffraction peaks indicates the nanostructure nature of the samples. Surface morphology of the samples was studied by Scanning Electron Microscope (SEM). Compositional Elemental analysis of data is obtained from Energy Dispersive Analysis of X-ray (EDAX) plots. [ABSTRACT FROM AUTHOR]

The present investigation aims to demonstrate the potentiality of Ca3Y2Si3O12 doped with Ce3+ and Tb3+ along with Tb3+ and Ce3+ co-doped phosphors, which are prepared by a sol-gel method. Photoluminescence (PL) spectra revealed a brighter and broader violet-blue emission from the Ce3+ [5d(²D) → ²F5/2,7/2] and an intense sharp green emission (545 nm) from the Tb3+ (5D4 → 7F5) doped phosphors. For Tb3+ and Ce3+ co-doped phosphors, a strong green emission (5D4 → 7F5) was observed upon excitation with a UV wavelength (242 nm). An energy transfer phenomenon from Ce3+ to Tb3+ was observed in these co-doped nanocrystalline phosphors. It was also observed that their PL intensity depends on the doping concentration of Ce3+, while the concentration of Tb3+ is fixed. The mechanism involved in the energy transfer between Ce3+ and Tb3+ was explained with an energy level diagram. For these phosphors, X-ray diffraction and transmission electron microscopy were carried Out to understand their structural properties. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the results of MgAl2O4:Eu3+ red emitting phosphor which has been characterized by X-ray diffraction, FESEM, FT-IR and photoluminescence spectra. The ultraviolet excitation at 393nm has been chosen because it has got maximum excitation intensity. These phosphors show different emissions of Eu3+ corresponding to 5D0 → 7F J=0,1,2,3,4 transitions which lie in the wavelength range from 550 to 700nm. One particular transition 5D0 → 7F2 which is centered at 615nm has been known as a hypersensitive emission which obeys the selection rule of (ΔJ =2) resulting in a strong and intense red emission. The lifetime, luminescence quenching has been discussed and the mechanism involved in the generation of red emission has also been explained. [Copyright &y& Elsevier]

Co1 + x Si x Fe2 − 2 x O4 ferrite system has been studied to estimate the influence of Si and Co substitutions together on the magnetic and magnetostrictive properties. The samples were prepared by standard double sintering ceramic technique. X-ray diffraction patterns of the study confirm spinel crystal structures. Hysteresis and magnetostriction measurements were made on all the samples at room temperature. Mössbauer spectra were also made both at 300 K and at 4 K under the applied field of 5 T in the direction of gamma ray. Nominal decreases in Curie temperature and saturation magnetization were observed. The strain derivative, which relates to stress sensitivity, is observed to increase from 1.13 × 10 − 9 to 2.51 × 10 − 9 Å − 1 m for x = 0.2 silicon concentration. The variations are explained on the basis of the strength of the exchange interactions between cations, and anisotropy modifications induced by migration of cobalt ions. The results demonstrate the possibility of controlling the magnetic and magnetomechanical properties through Co and Si substitutions. [ABSTRACT FROM AUTHOR]

Emission spectral results of Pr3+ & Ho3+ ions doped Ca4GdO(BO3)3 powder phosphors are reported here. XRD, SEM and FTIR measurements have been carried out for them. The emission spectrum of Pr3+: Ca4GdO(BO3)3 has shown an emission transition 1D2 → 3H4 at 606 nm with λexci = 480 nm (3H4 → 3P0) and Ho3+: Ca4GdO(BO3)3 phosphor has shown an emission transition 5S2 → 5I8 at 549 nm with λexci = 447 nm (5I8 → 5F1). Emission performances of these two phosphors have been explained in terms of energy level diagrams. [ABSTRACT FROM AUTHOR]

Abstract: Emission spectrum of Dy3+:Ca4GdO(BO3)3 powder phosphor has been analyzed. Two emission bands at 492 and 588nm with λ exci =311nm (6H15/2 → 4L19/2) have been measured from this phosphor. For the intense yellow emission at 588nm (4F9/2 → 6H13/2), its lifetime has been measured. Emission performance of this phosphor has been explained in terms of an energy level diagram. Besides carrying out the emission analysis, XRD, SEM and FTIR studies have also been carried out in order to understand the nature and structural details of the optical material studied. [Copyright &y& Elsevier]

Bismuth ferrite-based multiferroic composites, x⋅Bi0.95Mn0.05FeO3 − (1 − x)⋅Ni0.5Zn0.5Fe2O4, where x takes the values of 0.2, 0.4, 0.5, 0.6 and 0.8, have been prepared by combining sol-gel autocombustion and solid-state methods. Phase identification of the samples was done by X-ray diffraction analysis. SEM-EDX measurements on the samples were used to evaluate the microstructural aspects and quantitative evaluation of the samples. Room temperature P-E loop measurements on the samples were done under the application of external electric fields in the range from 0 to 6 kV/mm at a frequency of 50 Hz to understand the ferroelectric strength of the compounds. Magnetic studies on the samples were made by M-H loop measurements in the field range of ± 10 kOe. Magnetoelectric coupling measurements were made using a dynamic lock-in test set-up. The results indicate that the mixing of nickel-zinc ferrite in Bi0.95Mn0.05FeO3, in spite of the enhanced conductivity, has produced considerable improvements in saturation magnetization while retaining the remnant ferroelectric polarization in reasonable magnitudes to obtain improved M-E coupling. Among all the composites, the composite with x = 0.5 has resulted better M-E performance. [ABSTRACT FROM AUTHOR]

Na+ ion-conducting solid electrolyte of sodium nitrate (NaNO3) and Sr(NO3)2 mixed crystals were grown by slow evaporation technique. XRD, FTIR, SEM characterizations and AC, DC conductivities were carried out on the pellets. Conductivity in these mixed solid electrolytes was noticed to increase with increase in m/o Sr(NO3)2 upto 14.68 followed by decrease. The conductivity in 14.68 m/o Sr(NO3)2 is more than one order of magnitude as compared to NaNO3 in the extrinsic region. Ionic transport in these mixed systems is explained. [ABSTRACT FROM AUTHOR]