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The effect of strontium (Sr) doping on the structural, magnetic, electrical, and thermal properties of Pr1-xSrxCoO3 (0.1 ≤ x ≤ 0.5) has been studied. The samples were synthesized by using the conventional solid-state reaction method. The Rietveld refinement of X-ray diffraction patterns confirms the single-phase composition with orthorhombic (Pbnm) perovskite symmetry. The magnetization measurements revealed the paramagnetic to ferromagnetic transition and the transition temperature (Tc) increased with increasing Sr doping. The effective magnetic moments determined by the Curie-Weiss law show an increase in the Sr concentration. The temperature dependence of electrical resistivity suppressed with increasing the Sr content. Moreover, all the compounds other than x = 0.5 show the semiconducting nature. All semiconductor compositions (x = 0.1, 0.2, 0.3, and 0.4) in the high temperature region can be explained within the framework of the small polaron hopping model and the variable range hopping model, whereas the metallic composition (x = 0.5) is explained by electron-electron, electron-phonon, and electron-spin fluctuation scattering processes. The Seebeck coefficient (S) for all the samples except x= 0.5 is found to be positive, thereby confirming the applicability of the small polaron hopping model in the high-temperature region. The sample with x = 0.5 exhibits a crossover in S from positive to negative values and again attains a positive value. [ABSTRACT FROM AUTHOR]

• Friction stir welding of AZ31 was performed. • Rietveld refinement approach was applied to identify the weight fraction of various phases. • Various mechanical testing was done. Also, low temperature Charpy impact test was performed. • Microstructural behaviour wad studied with the help of SEM, Optical, EDS and XRD. In this research, phase identification and crystallographic parameters were determined using Rietveld refinement approach to assess the influence of the second-phase (Intermetallic compounds) on the mechanical and microstructural characteristics of friction stir welded AZ31 alloy. The Rietveld-fitted XRD analysis determined welded samples consist of a mixed phase (cubic and hexagonal) comprising fractional value of 99.52 % Mg and 0.48 % Al 12 Mg 17. Based on the results, it was found that the fractional percentage of IMCs directly influences the mechanical properties. [ABSTRACT FROM AUTHOR]

We have investigated the structural, magneto-resistive, electrical, and thermal transport properties of monovalent substituted polycrystalline Nd0.7Sr0.3−xAxMnO3 (x = 0, 0.1 and A = Na, Ag, K) compounds. The Rietveld refinement of the X-ray diffraction patterns reveals that all samples crystallize in orthorhombic structure with Pnma space group. The scanning electron microscopy micrographs evidenced that the grains acquire uniform morphology, nearly spherical, and unequal grains in all the studied samples. The decrease in metal-insulator transition temperature on the monovalent substitution is a result of reduced double-exchange interactions. Further, above the metal-insulator transition, electrical transport properties are analyzed through variable range hopping and small polaron hopping models. The substitution of monovalent cations enhanced the experimental parameters like hopping distance and activation energy, while the density of state at the Fermi level decreased significantly. On the monovalent doping, the samples showed very high magnetoresistance (MR%), and the temperature coefficient of resistance (TCR%) makes them prospective candidates for advanced uncooled infrared bolometers. The thermoelectric power (S) demonstrates a positive to a negative crossover, and the value of S increased in doped samples. At the higher temperatures, the small polaron is responsible for the conduction process. [ABSTRACT FROM AUTHOR]

• Ca 4 Mn 3-x W x O 10 (x = 0, 0.05, 0.10) synthesised using a solid-state reaction technique. • Rietveld refinements of high-quality powder XRD show good convergences. • X-ray photoelectron spectroscopy show the mixed oxidation state of Mn cations. • Semiconducting behaviour of the samples is consistent with the VRH and SPH models. • Thermopower study reveals that all samples have a small polaron hopping mechanism. This report comprehensively investigates the crystal structure, magnetism, and transport properties of tungsten (W6+) substituted polycrystalline Ca 4 Mn 3-x W x O 10 (x = 0, 0.05, 0.1) compounds. The compounds were synthesized using the solid-state method and found to exhibit a single-phase orthorhombic structure confirmed by the Rietveld refinement. The substitution of (W6+) induces a change in the Mn octahedron and enhances the unit cell volume. The morphology indicates the crystalline nature of all the samples. The FTIR spectroscopic study revealed the position of the IR bands, which is highly sensitive to the oxidation state of Mn-ions. The shift to higher wavenumbers indicates reduced oxidation from Mn4+ to Mn3+ species. The appearance of the Mn4+ oxidation state in (x = 0) and the emergence of Mn3+ on W6+ substitution for (x = 0.05, 0.1) compounds are explored. The electrical resistivity plots revealed that compounds are semiconducting. The magnitude of resistivity decreases with W6+ substitution. The reported compounds exhibit a significant negative magneto-resistance towards lower temperatures. The compounds also demonstrate short-range ferromagnetic (FM) behavior attributed to the charge compensation effect's double exchange interaction (DE) connecting Mn4+ and Mn3+. The negative value of thermoelectric power (S) suggests the presence of charge carriers such as electrons, and the value of S first increased and then decreased in doped samples. The conduction in the studied compound is attributed to small polaron hopping. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Synthesis of bulk La 0.7 Ba 0.3 Mn 1−x Al x O 3 (0 ≤ x ≤ 0.15) compounds with Al3+ substitution at Mn-site. • Significant crystal structural-relaxations in terms of bond-length, bond-angle and tolerance factor values. • Methodological investigation of magneto-transport and thermoelectric properties. • Enhanced magnetoresistance and determination of several other electronic-transport parameters that govern charge conduction. • Analysis of thermoelectric power via five degree polynomial fit and SPH/VRH polaron hopping mechanism. Abstract This report presents the structural, magnetoresistance, electrical and thermal transport properties of Aluminium substituted La 0.7 Ba 0.3 Mn 1−x Al x O 3 (0 ≤ x ≤ 0.15) compounds synthesized by solid state reaction method. To obtain crystallographic parameters, the X-ray diffraction patterns are fitted in R-3c space group with Rietveld refinement method. The resistivity and magneto-transport measurements are performed using standard four-probe assembly with and without magnetic fields. The peak resistivity ρ peak is noted at Metal-Insulator Transition temperature (T MI) and lowering in T MI is observed for higher concentrations of Al3+. The resistivity data have been analyzed in two parts. Firstly, in the metallic region below T MI the resistivity data is fitted with three degree polynomial. Secondly, in the semiconducting region above T MI data have been fitted with Variable Range Hopping (VRH) and Small Polaron Hopping (SPH) models. The Seebeck coefficients found to be positive throughout the temperature range (10 K–300 K) with holes as dominating charge carriers. Similar to the resistivity profile, in metallic region the thermo-power is explained with qualitative model based on diffusion, magnon-drag, phonon-drag and spin fluctuation contributions whereas the semiconducting region is explained with small polaron hopping model. [ABSTRACT FROM AUTHOR]

[Display omitted] • Samples were synthesized via solid state reaction technique. • XRD and Raman Spectra successfully probe crystalline nature of samples. • The Y substitution increased saturation and remnant magnetization significantly. We report a comprehensive study on the correlations of structural, magnetic, and electronic properties of Y substituted double perovskite La 2-x Y x CoMnO 6 (0 ≤ x ≤ 0.3) compounds. The Rietveld refined X-ray diffraction patterns reveal that all synthesized compounds crystallize in monoclinic structure with the P 21 /n space group. Raman spectra affirm the presence of well-defined bands, assigned to the double perovskite structure. The temperature dependence of electrical resistivity indicates the semiconducting nature of the compounds without any transition and is effectively probed by Variable range hopping model. The application of a magnetic field suppresses the resistivity to exhibit significant low-temperature magnetoresistance. The paramagnetic to ferromagnetic transition temperature (Tc) decreased but saturation/remnant magnetization increased with increasing Y doping. The effective magnetic moments determined by the Curie-Weiss law show a decrease in the Y concentration. The substitution of iso -valent Y at the La site induces structural compression which is strongly correlated to the enhancement of effective magnetization values. [ABSTRACT FROM AUTHOR]

We have synthesized PrSrAgMnO (0 ≤ x ≤ 0.1) compound by conventional solid state reaction method at different sintering temperature. The structural parameters obtained using Rietveld refinement of X-ray diffraction data which showed perovskite structure with orthorhombic ( Pnma) symmetry without any detectable impurity phase. The grain growth and grain connectivity extensively improved at higher sintering temperature with doping concentration. Depending upon the doping and the increment of sintering temperature, the samples showed very high magneto-resistance (MR%) and temperature coefficient of resistance (TCR). An improvement in magneto-resistance and TCR with increasing the sintering temperature i.e., 1200-1300 °C which make the compound more promising for scientific and technological applications. [ABSTRACT FROM AUTHOR]