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A supercapacitor (SC) is considered to be one of the best energy storage devices due to its high-power density, long lifespan, fast charge storage capability, and eco-friendliness. Ceramics with low-cost, nontoxic, high efficiency, and stability are the suitable and promising materials for performed supercapacitors at room temperature. As proposal, we synthesized by sol–gel method the ceramics Ba(Ti1-xMnx)O3 (where x = 0, 1, 2, or 3%) to study the effect a low rate of manganese doping on their morphological, structural, dielectric, and optical properties. The microstructure of the sintered ceramics was examined using scanning electron microscope (SEM), and the results reveal that the average grain size (AGS) of the ceramics (0.663–1.018 μm) increases with increasing Mn doping content. The optical behavior was studied by UV–visible spectroscopy, and the results indicate that Mn doping reduces the band gap (Eg) from 3.27 to 2.79 eV thus, the possibility of using these materials in photocatalyze applications. The dielectric properties of all studied samples were investigated at the temperature range 30–400 °C and frequency range 103–106 Hz. Significant modification in dielectric permittivity and an appreciable decrease in dielectric losses were observed when adding Mn2+ ions to BaTiO3 ceramics. Variations in dielectric properties and AC conductivity, as a function of frequency, reveal a relaxation mechanism related to the Maxwell–Wagner interfacial polarization. The obtained results suggest the use of prepared ceramics in capacitor and actuator applications at room temperature (RT). [ABSTRACT FROM AUTHOR] more...

In this current study, we present a detailed investigation on the structural, magnetic, magnetocaloric and electrical properties for La0.4Ag0.1Caipt>0.5MnO3 (S1) and La0.5Ca0.4Ag0.1MnO3 (S2) polycrystallines samples prepared using the well-known sol–gel method. Our analysis of X-ray diffraction, employing Rietveld refinement, reveals that these samples crystallize in the orthorhombic structure with Pnma space group. The results demonstrated that magnetization measurements as a function of temperature, under different magnetic fields for the sample (S1), exhibit two distinct phase transitions at TC1 = 48 K and TC2 = 186 K, whereas sample (S2) displays a single transition at 261 K. Based on the magnetic field dependence of magnetization, M(H), and applying the thermodynamic Maxwell equation, the magnetic entropy change |ΔSm| of the studied samples (S1) and (S2) was determined. Electrically, we observed an upturned region of resistance at low temperature, and this recovery of the resistance is significantly influenced by the external magnetic field. [ABSTRACT FROM AUTHOR] more...

The new spinel ferrite has garnered significant attention and has piqued the broadest interest among scientists due to its versatile and promising features, as well as its wide range of applications. In this study, we outline the process of synthesizing nano-sized Li–Cr ferrite powder, which exhibits remarkable dielectric relaxor activity when exposed to elevated temperatures. The study primarily focuses on investigating the structural, electrical, and optical properties of these Li–Cr ferrite particles. X-ray diffraction measurements confirmed the well-arranged inverse-cubic spinel structure of the material. The sample’s nanostructural properties were examined using scanning electron microscopy. The sample’s well-organized inverse-cubic spinel structure was confirmed using Fourier transform infrared spectroscopy examinations. The optical properties of our sample, as measured by UV–Visible spectroscopy, revealed a bandgap value of 2.6 eV makes it interesting for optoelectronic applications. The investigation focused on dielectric relaxation and electrical characteristics using impedance spectroscopy. It was shown that the AC conductivity follows Jonscher’s law, and the Non-overlapping Small-Polaron Tunneling model was developed to elucidate the conduction mechanism. The impedance spectra’s Nyquist plot confirmed the presence of grain boundary relaxation in the temperature ranges of 300–370 K and 560–660 K. Additionally, the interface, consisting of both the grain boundary and electrode effect, had a substantial influence between 380 and 550 K. An appreciable value for the temperature coefficient of resistance is observed. The results obtained demonstrate that the synthesized powder is well-suited for utilization in high-energy storage, low-temperature co-fired ceramics technology and bolometer applications. [ABSTRACT FROM AUTHOR] more...

In this study, we give a thorough evaluation of the structural, magnetic, and magnetocaloric properties in iron-rich PrFe 11 Ti intermetallic alloy with ThMn 12 -type structure using a combination of experimental and theoretical analysis. X-ray diffraction coupled with Rietveld refinement was used to characterize the structure, which revealed a unique tetragonal crystal structure with I 4 / m m m space group. The 8 i site was identified as the preferred site for the Ti atom. This finding was confirmed by various techniques, including XRD, DFT, and Mössbauer spectrometry. Magnetic properties were studied through intrinsic magnetic measurements and magnetocaloric effect analysis. Mössbauer spectroscopy was employed to probe the local magnetic environment and for further characterization of the material's magnetic properties. The experimental results were complemented by theoretical calculations based on density functional theory (DFT). A promising magnetocaloric effect is observed, with a significant maximum magnetic entropy ( − Δ S M max = 2.5 J·kg − 1 ·K − 1 ) and a relative cooling power about 70 J·kg − 1 under low magnetic field change μ 0 Δ H = 1.5 T. Overall, our results provide a deeper understanding of the structural and magnetic properties of the material under study and demonstrate the effectiveness of the combined experimental and theoretical approach in the investigation of complex materials. The insights gained from this study could have implications for the development of advanced magnetic materials with enhanced properties for potential magnetic applications. [ABSTRACT FROM AUTHOR] more...

This paper presents a detailed study in the critical region around the Curie temperature to determine the universality class of the Sm 2 Ni 17 intermetallic compound. The magnetocaloric effect has been studied on the basis of experimental measurements of magnetization. Maxwell's relation and a phenomenological model are employed to find the change in magnetic entropy. The compound Sm 2 Ni 17 presents a variation in entropy with a moderate maximum and a wide range of operating temperatures. Numerous approaches have been used to explore the spontaneous magnetization behaviour and inverse of the susceptibility, including the modified Arrott technique, the Kouvel–Fisher approach, and the fitting of the critical isotherm. The scaling hypothesis has been used to confirm the validity and interdependence of the critical exponents associated with these phenomena. [ABSTRACT FROM AUTHOR] more...