Analysis Of Diffraction Patterns Research Articles

Mechanical Performance Optimization and Microstructural Mechanism Study of Alkali-Activated Steel Slag–Slag Cementitious Materials

The optimal proportion of alkali-activated steel slag–slag cementitious materials is investigated by considering the combined effects of steel slag content, alkali content, water glass modulus, and water–binder ratio using the Box–Behnken design in response surface methodology. Qualitative and semi-quantitative analyses of X-ray diffraction (XRD) patterns and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) images are conducted. The microstructural mechanism is elucidated based on the chemical composition, surface morphology, and microscale pore (crack) structures of the samples. A microreaction model for the alkali-activated steel slag and slag is proposed. The optimal composition for alkali-activated steel slag–slag cementitious materials is as follows: steel slag content, 38.60%; alkali content, 6.35%; water glass modulus, 1.23; and water–binder ratio, 0.48. The strength values predicted by the response surface model are p1d = 32.66 MPa, p7d = 50.46 MPa, and p28d = 56.87 MPa. XRD analysis confirms that the compressive strength of the sample is not only influenced by the amount of gel formed, but also, to a certain extent, by the CaCO3 crystals present in the steel slag, which act as nucleation sites. The SEM-EDS results confirm that the gel phase within the system comprises a hydrated calcium silicate gel formed through the reaction of volcanic ash and geopolymer gel formed through geo-polymerization. Analysis of the pore (crack) structure reveals that the compressive strength of the specimens is primarily influenced by porosity, with a secondary influence of the pore fractal dimension.

Characterization of starches isolated from Mexican pulse crops: Structural, physicochemical, and rheological properties

This work aimed to characterize and compare the physicochemical properties of four pulse starches: bean, chickpea, lentil, and pea. Chemical proximate analysis, elemental composition, morphological grain characterization, crystalline structure, thermal analysis, FTIR analysis, and pasting properties were conducted. The proximate analysis shows that these starches have low fat, mineral, and protein content but high amylose values ranging from 29 to 36 % determined by colorimetry. Despite the high amylose content, the starches did not exhibit the typical behavior of an amylose-rich starch, with high peak viscosity and low breakdown and setback. It was found that this behavior was likely due to the large granule size of the ellipsoidal, spherical, and kidney-shaped granules and the high content of some minerals such as Na, Mg, K, Fe, Mn, P, and Si. The study also found that all pulse starches simultaneously contain monoclinic and hexagonal crystals, making them C-type starches. The findings were verified through the Rietveld analyses of X-ray diffraction patterns and differential scanning calorimetry, in which bimodal endothermic peaks evidenced both types of crystals being gelatinized.

Tb-doped strontium aluminate nanophosphor: Cytotoxicity, phytotoxicity, and bioimaging in plant cells

This study explores the novel application of terbium-doped strontium aluminate nanoparticles for fluorescence imaging in plant cells. The study encompasses microwave assisted solid state synthesis as well as the structural and optical characterization of terbium-doped strontium aluminate nanophosphors, their toxicity studies in plant and animal cells and their use as a fluorescent dye for plant imaging. The X-ray diffraction pattern analysis, along with Rietveld refinement studies, show the formation of SrAl2O4 as a dominant crystalline phase. Photoluminescence investigations demonstrate green emission from Tb3+ transition levels. In vitro biocompatibility of terbium-doped strontium aluminate nanophosphors was studied using L929 fibroblast cells. The plant Clitoria ternatea was used to examine phytotoxicity. The samples' potential for bioimaging was further investigated. Our findings reveal improved growth of seedlings, positioning these nanoparticles as promising tools in plant-related research. This study advances our understanding of nanoparticle-plant interactions and holds potential for transformative applications in agriculture.

Aluminium substitution affects jarosite transformation to iron oxyhydroxides in the presence of aqueous Fe(II)

Jarosite is an abundant mineral in acidic environments, often found in acid sulfate soil (ASS) and acid-mine drainage (AMD). As a store of Fe, K, S and acidity, and a scavenger for major and trace elements, jarosite plays an important role in the biogeochemistry of acid sulfate environments. When ASS and AMD become anoxic, reducing conditions can set in, producing conditions that are outside the thermodynamic stability field of jarosite. In this study, we investigated the transformation of synthetic and natural jarosite with various degrees of Al-for-Fe substitution under circumneutral anoxic conditions in the presence of Fe(II), to understand the rates and pathways of jarosite and Al-jarosite transformation, the role of competing transformation pathways, the fate of Al during transformation and the different reactivity of natural and synthetic Al-jarosite. Synthetic jarosite (containing 0 %–7 % Al-for-Fe substitution) and a natural Al-substituted jarosite sample from an ASS in Thailand were suspended in solutions of 57Fe(II) at pH 7 for 24 h under anoxic conditions. The chosen experimental conditions mimic the Fe(II) concentrations and pH found in flooded ASS under reducing conditions. Changes in mineral composition of the suspensions were determined by Rietveld analysis of X-ray diffraction patterns at six time points. The fate of Al was determined by XRD, Raman spectroscopy and energy dispersive X-ray spectroscopy analysis of the jarosite and product minerals. Different transformation pathways that occurred simultaneously were traced by using 57Fe Mössbauer spectroscopy and aqueous Fe isotope composition. The analysis showed that 7 % Al-for-Fe substitution in jarosite more than halved the mineral transformation rate compared to unsubstituted jarosite, regardless of the Fe(II) concentrations. Indeed, 7 % Al-for-Fe substitution had a greater effect on the transformation rate than an order-of-magnitude decrease in the Fe(II) concentrations in all Al-for-Fe substitution treatments. The transformation products in all samples were goethite, lepidocrocite and ferrihydrite, with minor amounts of magnetite forming from jarosite with no or low Al-for-Fe substitution reacted with high Fe(II) concentrations. Lepidocrocite was the dominant product in reactors without aluminium, but lepidocrocite was not strongly enriched in 57Fe, suggesting that it may not have formed exclusively from Fe in solution during the Fe(II)-catalysed transformation of other minerals. In high-Al systems, lepidocrocite appeared to be a sink for Al, although its formation in Al-rich samples was suppressed. Natural jarosite reacted more than an order of magnitude more slowly than the synthetic jarosite and Al-jarosite, indicating that the properties of the synthetic jarosite do not completely account for the stability of natural jarosite under anoxic circumneutral conditions. The results provide an important baseline for understanding the drivers of jarosite transformation or stability in ASS and AMD.

Design and Fabrication of Two Heterojunction Devices Performance for Photodetectors Applications

Hydrothermal preparations have been made form vanadium oxygen systems V2O5 and VO2 NPs prototype to design photodetectors. In comparison, the films' polycrystalline structure can be seen in analysis of x-ray diffraction (XRD) pattern, which has 7 and 14 peaks with crystallite sizes = 19.59 for V2O5 and, crystallite sizes = 12.92 nm, for VO2. The grains had large, neatly separated conical columnar growth combined grains throughout the surface, with some of the columnar grains coalescing in a few spots, according to the analysis from atomic force microscopy (AFM). It is revealed that the average size of particle of V2O5 =29.58 nm and for VO2 = 16 nm, with rms roughness of 6.8 nm and 21.3 nm respectively. Also, the optical energy gap of V2O5 = 2.6 eV, whereas energy gap of VO2 = 1.36 eV. In addition, it was discovered that the reflectance increased in the visible and infrared regions to register 0.09 and 0.07 respectively. The maximum values of the refractive indices for V2O5 and VO2 were 2.6 and 1.9, respectively. Two types of hetero-junction photo-detectors Ag/VO2/PSi/n-Si/Ag and Ag/V2O5/PSi/n-Si/Ag have been fabricated and characterized. The proposed results of Ag/ V2O5 /PSi/n-Si/Ag heterojunction Photo-detector at different concentrations from PMMA: Acetone responsivity was 0.7A/W at 850nm and, the remarkable detectivity = 4.1 x 1012 (1/W) .cm. Hz0.5, while, highest values of the detectivity in Ag/VO2/PSi/n-Si/Ag = 3.3 x 1012 (1/W) .cm.Hz0.5 at wavelength equal and greater than 850 nm. Index Terms— vanadium dioxide, hydrothermal, PVP, PMMA, Acetone, Photo-detector.

IQual: a new computer program for qualitative phase analysis with efficient search–match capability

iQual is a new computer program developed for qualitative phase analysis using powder diffraction data. It is based on a new database named Crystal_db, derived from the latest Crystallography Open Database. Crystal_db has been created with organized functional modules and optimized index structures, greatly enhancing the database's search efficiency. The iQual program offers users a wide range of querying capabilities and convenient visualization features. In addition to providing an efficient interactive interface, the program combines with the optimized database to enable efficient searching for and finding of the data entries that best match the experimental data for qualitative analysis of X-ray diffraction patterns. The highlight of this search–match method lies in an effective two-step approach that makes full use of the database structure. A preliminary screening is adopted, based on the five strongest diffraction peaks of each candidate phase, prior to scoring the candidate phases. Matrix operations in both screening and scoring processes enhance the program's efficiency.

SYNTHESIS OF MULTICOMPONENT HEAT-SHIELDING RADIATION-RESISTANT CERAMICS WITH VARIATION OF STOICHIOMETRY OF CERAMIC COMPONENTS

The paper presents the results of obtaining multicomponent heat-protective radiation-resistant ceramic materials based on the WO3–Bi2O3–ZnO–TeO2–CeO2–ZrO2 compounds obtained by mechanochemical solid-phase synthesis with further annealing at a temperature of 1000 °C. The introduction of doping substances into the structure in the form of metal oxides makes it possible to prevent undesirable structural changes in ceramics and improve the durability and stability of the system. The choice of the synthesis of ceramics based on zirconium oxide is associated with the presence of several valuable physical and mechanical properties of the substance, and, as a consequence, the possibility of application in the field of functional materials for use in a variety of technical fields. The processes of phase formation in multicomponent ceramics based on oxide refractory compounds (WO3, Bi2O3, ZnO, TeO2, CeO2, ZrO2) were studied by scanning electron microscopy, energy dispersive and x-ray phase analysis methods. Using a combination of the presented methods, the following results were obtained, which make it possible to comprehensively characterize the samples under study, as well as establish the dependence of the influence of variations in the oxides used on the phase composition and morphological features of the ceramics. Analysis of morphological parameters showed that with increasing dopant concentration, a denser structure of agglomerates is formed, which is associated with sintering of particles at higher dopant concentrations. According to the obtained results of energy dispersive analysis, it was found that the addition of ZrO2 results a slight redistribution of elements in the structure, so the atomic content of Ce, W, Bi, and Te decreased by 2.58; 3.38; 2.12; 1.91 times, respectively, and the atomic content of Zn increased by 1.32 times. Analysis of diffraction patterns showed that the studied samples WO3-Bi2O3-ZnO-TeO2-CeO2-ZrO2 are characterized by the content of Zn3(TeO6), ZnTeO3, CeO2, Bi2O3, Bi2WO6, ZnWO4, Ce5Zr3O16, ZnO, (Zr0.98Ce0.02)O2 phases.

Effect of annealing temperature and doping concentrations on structure and optical properties of Eu3+-doped TiO2 nanomaterials

In this study, we successfully synthesized europium-doped TiO2 (TiO2:Eu3+) nanomaterials (NMs) with crystalline sizes ranging from 6.5 to 71.7 nm through a sol-gel method. Analysis of X-ray diffraction (XRD) patterns and ultraviolet-visible (UV-Vis) spectra indicates that the substitution of smaller-sized Ti4+ ions (0.745 Å) by larger-sized Eu3+ ions (0.947 Å) was more efficient at higher doping concentrations and annealing temperatures. Photoluminescence (PL) and photoluminescence excitation (PLE) spectra of the synthesized TiO2:7%Eu3+NMs exhibit a strong red emission band peaking at 613 nm and remarkable absorption in the blue light region centered at 463 nm, making them suitable for use in white light-emitting diode (WLED) applications. Our findings reveal that both annealing temperature and doping concentration significantly influence the structure and properties of these materials. Besides, the research team has seen, under the experimental conditions, the TiO2:7%Eu3+ sample annealed at 800°C exhibits the highest PL intensity. These results underscore the potential of the synthesized TiO2:Eu3+ NMs as red-emitting materials for WLED applications.

Enhancing thermoelectric behavior of Bismuth Selenide crystal via substitution of Sulfur and Tellurium

Sulfur and Tellurium substituted Bismuth Selenide (Bi2Se3-x-ySxTey, x = y = 0, 0.1, 0.15, 0.2) quaternary alloy crystals were synthesized by using vertical Bridgman technique. Energy dispersive analysis of X-rays confirmed elemental composition and purity of the grown crystals. Field emission scanning electron microscopy showed that the growth of crystals has occurred by layer growth mechanism. Rhombohedral crystal structure is validated through analysis of powder X-ray diffraction pattern. Thermoelectric parameters such as electrical conductivity, Seebeck coefficient and thermal conductivity were calculated from 303 K to 773 K and from that power factor as well as figure of merit have been determined for all grown crystals. Electrical conductivity significantly increased due to Sulfur and Tellurium incorporation and maximum value obtained is 147.72 S/cm at 503 K for Bi2Se2.6S0.2Te0.2. Seebeck coefficient and thermal conductivity showed decrement with incorporation of Sulfur and Tellurium. Reduction in thermal conductivity and enhancement in electrical conductivity resulted in the improvement of figure of merit. Sulfur and Tellurium substitution showed considerable improvement in ZT from 0.31 (533 K) for pristine Bi2Se3 to 1.28 (523 K) for Bi2Se2.6S0.2Te0.2.

Structural and cation distribution analysis of Nickel-Copper/Nickel-Magnesium Substituted Lithium Ferrites

Lithium ferrite (Li0.5Fe2.5O4) shows significant promise in electrical and electronic engineering. It possesses a crystal spinel crystal structure denoted as AB2O4, with "A" and "B" representing specific tetrahedral and octahedral lattice sites respectively. Analysis of X-ray diffraction (XRD) patterns aligns well with the JCPDS card (no. 38-0259), confirming the spinel structure with the Fd3m space group. However, an additional peak at 211 in the basic lithium ferrite suggests a subtle Fd3m to the P4132 phase change with a minor secondary hematite phase. Investigating the cation distribution in these ferrites is crucial for further exploration of their magnetic and dielectric properties. These ferrites find widespread applications in microwave technology and magnetic and electric energy storage devices.

Synthesis and Characterization of Aluminum Oxide Nanoparticles Prepared by Two Different Cold Plasma Jet Methods

In this paper, a cold plasma system utilizing a high voltage of 13.5 kV of alternative (AC) and direct current (DC) was used under atmospheric pressure with argon (Ar)-gas at a flow rate of 2.5 l/min and a flowing time of 4 min to synthesize aluminum oxide (AlO) nanoparticles (NP). From the results, when DC was used, it was found that the absorption spectrum starts at 303 nm and gradually falls to 870 nm. With AC, the absorption spectrum was at 330 nm and then began to fall to 902 nm. The energy gap when utilizing DC and AC was 3.49 and 3.44 eV respectively. The analysis of the X-ray diffraction (XRD) patterns showed the structure of the NPs was amorphous, matching the pattern 42-1746. At DC, the average size of NPs formed, as deduced from the XRD pattern, was 29.56 nm, and it was very close to what appeared in the field emission scanning electron microscopy (FESEM) images, in which the apparent NP size ranged between 20 and 50 nm. The XRD test gave an average NP size of 38.21 nm in AC, while the FESEM images showed a size range of 20 - 60 nm. At dc, the AlO NPs were aggregated and interconnected, and each set was connected to another set, as shown in the FESEM images. At AC, the shape of the synthesized AlO NPs was quasi-spherical, with slightly elongated particles connected.

PROCEDURE FOR DETERMINING THE NATURE OF CALCIUM CARBONATE FORMATION ON OILFIELD EQUIPMENT

In the article, the authors propose to use the method of X-ray diffraction analysis (XRD) to establish the nature of the formation of oilfield deposits using of calcium carbonate as an example. It was shown for the first time that comparative diffraction patterns of natural and technogenic carbonate mineral deposits of oilfield equipment differ significantly in the physical broadening of diffraction reflections. In addition, it has been established that the diffraction reflections of technogenic calcite are characterized by shifts to the region of large scattering angles. These facts are taken as the basis for establishing the nature of the formation of carbonate deposits using X-ray diffraction analysis. It has been shown that natural (core) carbonate minerals are characterized by narrow reflections with good resolution of doublet lines, while in minerals formed under borehole conditions, the diffraction maxima are much broader, and low-intensity reflections are not resolved. Precision analysis of diffraction patterns showed that the reasons for such atypical broadenings and shifts of reflections in technogenic mineral deposits are the relatively small sizes of grains — crystallites and high microdistortions of the crystal lattice compared to their natural analogues. It is shown that in order to establish the nature of carbonate deposits of oilfield equipment, it is necessary to measure diffraction patterns of natural and technogenic minerals under the same shooting conditions. Subsequently, the obtained diffraction patterns are analyzed and X-ray diffraction data on the microstructure of the studied minerals are determined. It has been established that in technogenic calcite the crystallite sizes in all arbitrarily selected directions (hkl) are more than 1.6 times smaller than in its natural analogue. The X-ray diffraction method has shown that the average value of microdistortion of the crystal lattice of technogenic calcite is 1.7 times greater than that of its natural analogue. As a result of comparing X-ray diffraction data on the fine structure of mineral deposits of oilfield equipment with those obtained from core material, the nature of the formation of the analyzed minerals is established. To confirm the XRD results, visual studies using scanning electron microscopy (SEM) were also carried out.

Integrated analysis of X-ray diffraction patterns and pair distribution functions for machine-learned phase identification

To bolster the accuracy of existing methods for automated phase identification from X-ray diffraction (XRD) patterns, we introduce a machine learning approach that uses a dual representation whereby XRD patterns are augmented with simulated pair distribution functions (PDFs). A convolutional neural network is trained directly on XRD patterns calculated using physics-informed data augmentation, which accounts for experimental artifacts such as lattice strain and crystallographic texture. A second network is trained on PDFs generated via Fourier transform of the augmented XRD patterns. At inference, these networks classify unknown samples by aggregating their predictions in a confidence-weighted sum. We show that such an integrated approach to phase identification provides enhanced accuracy by leveraging the benefits of each model’s input representation. Whereas networks trained on XRD patterns provide a reciprocal space representation and can effectively distinguish large diffraction peaks in multi-phase samples, networks trained on PDFs provide a real space representation and perform better when peaks with low intensity become important. These findings underscore the importance of using diverse input representations for machine learning models in materials science and point to new avenues for automating multi-modal characterization.

Biofabrication of silver nanoparticles using Uncaria tomentosa L.: Insight into characterization, antibacterial activities combined with antibiotics, and effect on Triticum aestivum germination

Abstract Herein, we used the aqueous extract of Uncaria tomentosa L. barks (Cat’s claw bark [CCb]) for the biofabrication of silver nanoparticles (CCb-Ag-NPs). The effects of different parameters (Uncaria tomentosa L. aqueous extract, silver nitrate [AgNO3] ratio, temperature, and pH) on the formation of the nanoparticles were investigated using UV scan as a preliminary tool for the detection of surface plasmon resonance of CCb-Ag-NPs. The optimal ratio was 1:7 (Uncaria tomentosa L. extract: 1 mM AgNO3 solution). Fourier-transform infrared spectroscopy revealed the functional groups of both CCb extract and the CCb-Ag-NPs, whose dispersion and quasispherical morphologies were characterized using scanning electron microscopy and transmission electron microscopy. Particle sizes ranged from 19.2 to 38.5 nm. The zeta potential of CCb-Ag-NPs was −34.44 mV. According to energy-dispersive X-ray analysis, the CCb-Ag-NPs contained 28.87% silver. The formation of Ag-NPs was also confirmed by X-ray diffraction pattern analysis. Pristine CCb-Ag-NPs showed antibacterial activity against three pathogenic bacterial strains: Escherichia coli (ATCC 25922), E. coli (ATCC 8739), and Pseudomonas aeruginosa (ATCC 90274). Antibacterial activity increased significantly after loading CCb-Ag-NPs on antibiotic discs containing meropenem and cefoxitin. Low concentrations of CCb-Ag-NPs also enhanced the germination percentage, coleoptile length, and radical root length of Triticum aestivum.

EPDFpy: A Python-based interactive GUI tool for electron pair distribution function analysis of amorphous materials

ePDFpy is an interactive analysis program with a graphical user interface (GUI), designed to process the electron Pair Distribution Function (PDF) analysis of diffraction patterns from Transmission Electron Microscope (TEM), to identify the local atomic structure of amorphous materials. The program offers a user-friendly Python-based interface, providing a straightforward and adaptable workflow for PDF analysis. Various optimization and fitting processes were implemented to accurately reduce the electron diffraction data, including center-fitting and elliptical correction of diffraction data. An improved parameter-estimation feature is available to enhance the efficiency of the fitting process, along with an interactive GUI. ePDFpy will be freely distributed for academic purposes, with additional features, including a beam mask drawing module. Program summaryProgram Title: ePDFpyCPC Library link to program files:https://doi.org/10.17632/sym3sfnh7w.1Developer's repository link:https://github.com/GWlab-SKKU/ePDFpyLicensing provisions: GNU GPLv3Programming language: PythonNature of problem: The general process of pair distribution function analysis consists of two major steps: image process on diffraction pattern and fitting appropriate parameters. Both of the procedures are affected by the user's proficiency, which can be responsible for producing inconsistent results and inefficiency. Thus, accurate calculation methods along with fully automated feature are required to enhance the quality of the analysis result.Solution method: ePDFpy offers an unbiased automated image process based on a computer vision algorithm to produce the consistent output of intensity profiles from diffraction patterns. In addition, converting the data structures into a multi-dimensional array enables efficient multi-parameter fitting features by performing parallel computation. All of these features are accomplished using various open-source libraries in the Python community, along with an interactive GUI.

Structural, morphological, dielectric, and electrical characteristics of a brownmillerite material for electronic devices: KBiMn2O5

The main objective this communication is to study the structural, morphological, dielectric, and electrical properties of a novel brownmillerite material, KBiMn2O5. Preliminary analysis of the X-ray diffraction (XRD) pattern with N-TREOR09 (trial and error method) with Le-Bail method shows monoclinic symmetry (a = 10.919 Å, b = 5.114 Å, c = 10.453 Å, β = 104.428˚). The examination of scanning electron microscopic spectrum provides the nature of the morphological surface of the sample having an average grain size of 19.89 μm. We have examined Maxwell-Wagner dielectric dispersion, relaxation, and transport mechanisms by analyzing the dielectric, impedance, and conductivity spectra across a wide range of experimental frequencies (1 kHz to 1 MHz) and temperatures (25°C to 500°C). The value of relative permittivity (εr) rapidly increases 200 (room temperature) to 85000 (500°C) with an increase in temperature from room temperature. The high value of εr shows colossal dielectric response (CDR) of the material. The low value of tangent loss (≥ 4.5) can also be applicable to electronic devices. On increasing frequency (1 kHz to 1 MHz), the activation energy of the charged ions from 0.391 eV to 0.328 eV shows a thermally activated relaxation mechanism in the material. The thermistor constant (β), determined as 6317.16, and the temperature coefficient of resistance (TCR) -0.00331 are suitable for high-temperature NTC thermistors, temperature sensors, and other electronic device applications. The study of room temperature non-Ohmic charge conduction and current-voltage charecteristics confirms the suitability of the material for devices.

Study of structural, dielectric, transport and optical properties of the CaMn0.94Ce0.06 O3 Ceramic

We report the structure, microstructure, dielectric, transport, and optical properties of the CaMn0.94Ce0.06O3 ceramic synthesized by the solid-state reaction method. Analysis of the X-ray diffraction (XRD) pattern of the sample adopts an orthorhombic crystal symmetry. A study of scanning electron microscope (SEM) micrograph shows the homogeneous distribution of the well-grown grains over the entire surface of the sample. The well-defined and distinct grain boundaries surrounding the compact grains may be a possible reason for a better conductivity mechanism in the sample. The study of the energy dispersive x-ray (EDX) spectrum provides information about the formation of high-purity samples and also confirms the presence of Ca, Mn, Ce and O in both weight and atomic percentages. The agglomeration rate during the sintering process may be a possible reason for a better dielectric and conductivity mechanism. Fourier-transform infrared spectroscopy (FTIR) study strongly supports the presence of all constituent element’s atomic vibration bands. The study of the UV visible spectra provides the idea of semiconducting nature and bandgap energy of 4.89 eV. At a low range of frequency, the presence of the Maxwell-Winger type of dielectric dispersion is confirmed. Dielectric properties were investigated, including conductivity, dielectric constant, dielectric loss, and complex modulus. According to impedance analysis, primarily the charge carriers’ long-range movement controls the conduction process. The semiconducting nature of the sample is confirmed by analysis of the Cole-Cole plots.

Identification of Crystal Structure, Surface Area, and Magnetic Properties of Mn<sub>0.25</sub>Fe<sub>2.75</sub>O<sub>4</sub>/rGO Nanocomposites

The aim of this research is to identify the crystal structure, surface area, and magnetic properties of The Mn0.25Fe2.75O4-rGO (reduced Graphene Oxide) nanocomposites (NCs). The synthesis of Mn0.25Fe2.75O4-rGO nanocomposites used the co-precipitation method. The rGO was obtained from the chemical reduction of GO by hydrazine hydrate as the reduction agent. The ratio between Mn0.25Fe2.75O4 nanoparticles and rGO was 1:1 that ultrasonicated at 200 Hz for an hour. The IR spectra of NCs from the FTIR instrument showed that the absorption band around 580 cm-1 and 1622 cm-1 corresponds to the stretching mode of Fe-O and C=C respectively. According to X-Ray Diffraction (XRD) pattern analysis, peak of Mn0.25Fe2.75O4 was detected on 2θ at 30.1°, 35.5°, 53.5°, 57.1°, 62.7° and the peak of rGO phases was amorphous that detected on 2θ between 17º and 30º. The XRD pattern analysis and FTIR spectra have proved the completion of NC’s synthesis. The crystallite size was between 10.3 nm by Scherer's formula. The Specific Surface Area showed that the surface area of the nanocomposites was 100.61 m2/g and the Molecular cross-sectional area was 0.162 nm2 by BET Theory. The Magnetic properties show that the NCs were Superparamagnetic material that has a saturation magnetization of 9.34 emu/g. The material has many potentials to be explored by the researcher around the world.

Effect of bismuth doping on structural, morphological, Griffiths-like phase, and magnetocaloric properties in La0.9−xBixBa0.1MnO3 (x = 0, 0.05, and 0.1)

In this recent work, we have carried out the structural, morphological, Griffiths-like phase, and magneto-caloric studies of sol–gel-synthesized, nanocrystalline manganite La0.9−xBixBa0.1MnO3 (x = 0, 0.05, and 0.1). The Rietveld analysis of X-ray diffraction patterns of nanocrystalline La0.9−xBixBa0.1MnO3 (x = 0, 0.05, and 0.1) confirm the single-phase nature and orthorhombic crystal structure with Pnma space group for all samples. The images acquired with a transmission electron microscope reveal the average particle sizes ranges from 32 nm to 65 nm. The temperature-dependent magnetization measurements, for 0.05 T external applied magnetic field, have revealed paramagnetic (PM) to ferromagnetic (FM) phase transition with transition temperatures (TC) ∼ 228 K, 219 K, and 233 K for x = 0, 0.05, and 0.1, respectively. The downward divergence of temperature dependence inverse susceptibility from the Curie-Weiss fit, indicates a pronounced Griffiths singularity in the samples. The positive slopes of Arrott plots for nanocrystalline La0.9−xBixBa0.1MnO3 (x = 0.05, 0.1) confirm the second-order magnetic phase transition. We have estimated the magnetic entropy change at different values of applied magnetic field for nanocrystalline La0.9−xBixBa0.1MnO3 (x = 0.05, 0.1) samples. Further, using this magnetic entropy data, we have also estimated the magnetic cooling capacity.

Exploration of Griffiths phase, spin glass behaviour and memory effect in a frustrated Al2MnCoO7 pyrochlore compound

Al2MnCoO7 pyrochlore compound has been synthesized following the multistep solid-state ceramics route. The compound exhibits a monoclinic structure, which was confirmed through the X-ray diffraction pattern analysis. The magnetization measurements in both zero-field-cooled (ZFC) and field-cooled (FC) modes indicate that the compound undergoes a phase transition from paramagnetic (PM) to antiferromagnetic (AFM) state at the Néel transition temperature TN ∼31 K. Notably, below TN, there is a substantial discrepancy between the ZFC and FC curves, which can be ascribed to the existence of competing ferromagnetic (FM) and AFM interactions, resulting in a glassy behaviour. Additionally, the compound demonstrates a Griffiths phase above TN, signifying the presence of ferromagnetic clusters within the PM region of the material. The spin-glass behaviour is confirmed by the shift of maxima towards higher temperatures with increasing frequency in the ac susceptibility measurement. The memory effect also confirms the spin-glass nature of the compound. The Arrott's plots confirmed that the magnetic phase transition in the material to be a second-order type. Additionally, the material exhibited a maximum magnetic entropy change (−ΔS) value of 1.08 J/kg.K and a relative cooling power of 36.60 J/kg under an applied magnetic field of 5 T.