The magnetocaloric effect (MCE) and electric-dielectric properties of the Nd-cobaltate perovskites Nd 0.6 Sr 0.4 Co 1Àx Mn x O 3 (x = 0, 0.3, 0.7 and 1) were investigated for possible use in magnetic cooling applications. Upon Mn substitution, the magnetic exchange interaction is affected by the (Mn 4+ /Mn 3+) ratio, which in turn impacts several physical properties. The XRD patterns of the synthesized composites revealed a single phase with an orthorhombic structure with space group Pbnm (62). The orthorhombic lattice distortion increases linearly with the Mn content, reaching a maximum value (D = 7.377 Â 10 À3) for Nd 0.6 Sr 0.4 MnO 3. The temperature and frequency dependence of the dielectric permittivity was studied and analyzed using Maxwell-Wagner interfacial polarization and Koops phenomenological theory. The rapid increase in magnetic susceptibility around the paramagnetic (PM)-ferromagnetic (FM) transition temperature T C is greatly affected by Mn substitution. The decrease in susceptibility with increasing temperature can be attributed to a charge ordering effect. The PM-FM transition occurs in the temperature range of 150-200 K. Moreover, the presence of spontaneous magnetization with second-order phase transitions is observed from Arrott plot isotherms. The MCE was also investigated by determining DS M and the relative cooling power (RCP), and the maximum value is found for Nd 0.6 Sr 0.4 Co 0.3 Mn 0.7 O 3. These results compare favorably with those reported for similar materials, indicating our materials as a possible candidate for use in magnetocaloric refrigerators.

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The present study, La0.7Sr0.3MO3 (M = Mn-, Co-, and Fe-), perovskite, has successfully been synthesized via co-precipitation and sol–gel auto-combustion. XRD, SEM, and EDX characterized the prepared samples. XRD and SEM showed that the as-prepared La0.7Sr0.3MnO3 and La0.7Sr0.3CoO3 have multiphase. La0.7Sr0.3FeO3, in comparison, is nanosized, has a single-phase perovskite, and has a rather homogenous particle size distribution. Additionally, EDX mapping analysis shows that all pieces are distributed uniformly. According to X-ray diffractometer results, all calcined powders contain 100% LSF, more than 15% perovskite phase of LSC, 47% LSM, and other secondary phases, such as cobalt oxide. Aِt room temperature and magnetic field of ± 20 kG, La0.7Sr0.3MnO3 exhibited weak ferromagnetic behavior in a low magnetic field, whereas diamagnetic behavior was seen in a high magnetic field. La0.7Sr0.3FeO3 samples behave as strong ferromagnetic. On the contrary, the photodegradation of La0.7Sr0.3MnO3 is 99% compared to 75% and 91% for other samples under UVC lights of wavelength = 254 nm. The degradation rate for La0.7Sr0.3MnO3 is 0.179 higher, about 3.25 and 2.23, than the other samples. A La0.7Sr0.3MnO3 nanocomposite performs as a photocatalyst to enhance the efficiency of methylene blue photodegradation. This study boosts good UVC photocatalysts with high efficiency for different kinds of dyes. Hence, the catalyst possessed high stability and efficiency for continuous wastewater treatment.

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The easiness of preparation and tailored properties of perovskite nanoparticles rendered them an important class of materials in the last decade. In this work, La 0.7 Sr 0.3 Fe 1-x M x O 3 (M=Mn, Co and x=0, 0.5) orthoferrites were synthesized using combustion method and examined using X-ray diffraction. The orthorhombic structure was clearly obvious with Pbnm space group without the need of any thermal treatment. Field emission scanning electron microscopy (FESEM) accompanied by Energy-dispersive spectroscopy studies were also performed, evidencing the similarity of both nominal and chemical compositions for the studied orthoferrites. The thermal dependence of the dielectric properties was investigated (from room temperature to 698 K) in the frequency range (70 Hz-5 MHz). Magnetic properties were investigated at room temperature and discussed.

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This research is focused on the effect of the nickel doping ratio on γ-ray attenuation radiological parameters for five compounds of chemical compositions BaMn1-xNixO3 (x=0.1,0.3,0.5,0, and 0.9), named Ni1, Ni3, Ni5, Ni7, and Ni9, in energy range between 0.015 and 15 MeV utilizing Phy-X/PSD software. Radiation parameters (MAC, LAC, HVL, TVL, MFP, ACS, ECS, Zeff, Neff, Ceff, Zeq, EBF, and EABF) are evaluated. Most of parameters depend profoundly on the photon energy. For instance, MAC is reduced from 137 to 0.133 cm 2 /g and LAC is increased from 775.7 to 0.75 cm -1 with increasing Eph (0.015 -15 MeV). Additionally, HVL and TVL increase from 0.0009 to 0.9 and from 0.003 to 3 cm respectively in between that energy range. Also, MFP increases from 0.001 to 1.3 cm but Neff, Ceff, Zeff , ACS, and ECS, decrease from 4×10 24 -2×10 24 , 1.6×10 10 -0.7×10 10 , 32 -15 electron/g, 100×10 -24 -1×10 -24 , and 3.3×10 -23 -0.007×10 -23 cm 2 /g at the energy 0.015-15 MeV. Furthermore, Zeq value is 19.3. Additionally, the exposure and energy absorption buildup factors (EBF and EABF) are determined to be 1-1.2, 2.7-29, 1.3-1.7, and 3.15-22 at various penetration depths (1-40 mfp). These values are independence of Eph at low mfp but at 40 mfp they are changed from 3to29. Maximum buildup parameters site in middle energy range, 0.2-1MeV. In another side, Most of such parameters are dependent on the Ni dopants. FNRCS values are 0.85 cm -1 . The present samples exhibit greater radiological properties than that published previously. These investigations are critical for the development of utilized semiconductor as detectors, attenuators, and protection radiation in various radiation safety applications fields.