Phase Transition of La0.62Sr0.38MnO3 Perovskite Manganites

Bulk and nano La0.62Sr0.38MnO3 perovskite manganite samples were prepared using solid state and sonochemical reaction respectively. The ultrasonic velocities measurement was made on prepared samples using ultrasonic through transmission method, at a fundamental frequency of 5 MHz over wide range of temperatures. The temperature dependence of the ultrasonic parameters shows an interesting anomaly in bulk and nano perovskite samples. The observed dramatic softening and hardening in sound velocities are related to phase transitions. Further, a decrease in grain size in the nanostructured sample leads to a shift in the ferromagnetic transition temperature (TC) from 375 to 370 K

Growth, Structural, Vibrational, Optical, Electrical and Thermal Properties of Transition Metal and Zinc Oxide added Glycine Semi-organic Crystal

The semi-organic crystals of the amino acid glycine were developed/grownup by the slow evaporation method from anaqueous solution in the manifestation/presence of zinc oxide and an additive Mn, Fe, Co, Ni, and Pb transition metals.Powder X-ray diffraction and elementary analyses of as-grown amino acid glycine crystals established/confirmed theexistence of additive spices which sanctuary the basic crystalline structure of α-glycine. The energy dispersive x-ray analysisspectrum (EDAX) and scanning electron microscope (SEM) analysis were carried out to confirm the composition ofelements present in the as-grown amino acid glycine crystals and to conclude the surface morphology. Theexistence/presence of functional groups and the nature of bonds present in as-grown amino acid glycine crystals wereassigned by Fourier-transform infrared spectroscopy (FTIR) and micro-Raman spectrums. The optical transparency and cutofwavelength have been predicted and the optical band gap of the ternary ZnO transition metal added crystals wascalculated. The emission property of the crystals was analyzed by using a Photoluminescence study. The electricalproperties of ZnO transition metallic additive added glycine semi-organic crystals were analysed using the impedanceanalyzer. The transition metals addition increases the conductivity of the glycine crystal. The dielectric analysis found thatcultivated crystals were potential candidates for NLO applications. Thermal studies have shown that harvested semi-organiccrystals have high thermal stability and high crystallization. The role of additives brings about significant changes in thephysicochemical properties of semi-organic α-glycine crystals for promising applications of NLO

Enhanced Mechanical, Thermal, Photoluminescence, NLO and Antifungal Activities of Magnesium Doped Ninhydrin Crystals

A normal way of slow evaporation method had been used to preparing pure ninhydrin (PN) and magnesium doped ninhydrin (M1N) single crystals. The research describes the various characterizations of the developed PN and M1N crystals. Monoclinic crystal structure with non centrosymmetric P21 space group were marked in the developed crystals. Additionally, to find out the various functional groups of the grown PN and M1N crystals Fourier’s transformation infra-red studies had been used for this research. Vicker’s microhardness tester had been used to identify the strength of the developed crystals. In energy dispersive x-ray analysis the presence of carbon, oxygen and magnesium into the crystal lattice was observed. In connection with this by using thermal analysis the decomposition point of the developed crystals were marked. The photoluminescence study was used to identify the excitation and emission peaks of the grown samples. Conclusively, by powder Kurtz-Perry method the second harmonic generation efficiency had been verified in a greater aspect of this research. The antifungal activity of the PN and M1N crystals was observed against two fungi such as Aspergillus flavus, Aspergillus niger

Effect of 200 MeV Ag16+ swift heavy ion irradiation on structural and magnetic properties of M-type barium hexaferrite

M-type barium hexagonal ferrite (BaFe12O19) has been synthesized by sol-gel auto combustion method. The synthesized material was irradiated with 200 MeV Ag16+ ions using the 15UD Pelletron tandem accelerator and the changes in structural and surface morphology of material were investigated. The pristine (as-synthesised) and irradiated samples were characterized using different experimental techniques like x-ray diffraction (XRD), Fourier-transform infrared spectroscopy, transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The strong absorption peak between 580 and 440 cm-1 in the infrared spectrum and XRD confirmed the formation of ferrite structure for both irradiated and pristine samples. XRD peaks for the irradiated barium hexagonal ferrite were slightly broadened when compared pristine ferrite samples. The crystallite size of the irradiated barium hexagonal ferrite was higher than that of pristine barium hexagonal ferrite and is consistent with TEM images. Both saturation magnetization and coercivity were decreased with irradiation. © 2019 IOP Publishing Ltd

Optical, Magnetic and Magneto-Transport Properties of Nd 1-xAxMn0.5Fe0.5O3-δ (A=Ca, Sr, Ba; x=0, 0.25)

The effect of A-site doping by alkaline earth metals (A = Ca, Sr and Ba) on optical, magnetic, and electrical properties of Nd1-xAxMn0.5Fe0·5O3-δ (x = 0, 0.25) has been investigated. The UV–vis absorption spectra show that the A-site doping decreases the absorption. Two values of optical band-gap energy (Eg) can be estimated for each studied sample: the higher Eg value is associated with the charge transfer involving iron cations and the lower Eg value – with the charge transfer via manganese cations. Partial substitution of neodymium by alkaline earth metals decreases the Néel temperature (TN) and induces significant irreversibility between the zero-field cooled (ZFC) and field-cooled (FC) data below TN. The field-dependent magnetization at 3 K indicates antiferromagnetic ordering with a spin canting. Temperature dependencies of resistivity demonstrate the change from metallic to semiconductor-type conduction (with increasing temperature) at T = Tp < TN. The Tp temperature significantly decreases with doping. The introduction of alkaline earth metals in Nd1-xAxMn0.5Fe0·5O3-δ noticeably reduces the resistivity in the semiconducting region. The small polaron hopping (SPH) mechanism of conduction is suggested at T > TN. Within the range of Tp < T < TN, the resistivity data are interpreted by the variable range hopping (VRH) mechanism. A significant value of magnetoresistance (∼44%) is observed only for Nd0.75Sr0·25Mn0·5Fe0·5O3-δ at 120 K. © 2020 Elsevier B.V.A. S. acknowledges, the financial support provided by the Department of Science and Technology (DST), Government of India (Indo-Russian project (INT/RUS/RFBR/P-239); A.R.G and V.A.C. acknowledge the financial support from Indo-Russian project (RFBR grant No 16-53-45010); and A.H. acknowledges financial support obtained from the Government of the Russian Federation by Act 211 agreement 02.A03.21.0006

Green synthesis of copper oxide nanoparticles using Amaranthus dubius leaf extract for sensor and photocatalytic applications

Copper oxide nanoparticles (CuO NPs) were produced through an environmentally friendly green synthesis. The characteristics of these green synthesized CuO NPs, including their structural, optical, morphological, and electrochemical properties, were examined using various characterization techniques. X-ray diffraction analysis revealed that the CuO NPs have a monoclinic structure with a C2/c space group. Electrochemical detection of glucose was carried out using cyclic voltammetry. The green synthesized CuO NPs exhibited excellent catalytic properties for both electrochemical sensing and photocatalysis. Significantly, these CuO NPs exhibited excellent selectivity and sensitivity in glucose detection, with a sensitivity of 370 μA mM−1 cm−2 and a detection limit of 1.0 μM. Furthermore, the CuO NPs demonstrated a substantial 84 % degradation of dyes within 150 min. These results underscore the potential of the green synthesized CuO NPs as a promising material for applications in both sensing and dye degradation

Structural studies of nano silica employing on-line ultrasonic studies

Monodispersed, nano silica particles have been prepared by sol-gel hydrolysis and condensation of the metal alkoxide using pH buffer. The prepared particles are characterised by XRD, FTIR, BET, SEM, TEM measurements. The measurements reveal that the size and shape of silica particles depend on concentration of water. In addition, the ultrasonic longitudinal velocity and attenuation of the nano silica particles have been measured at a frequency of 5 MHz over a wide range of temperatures from 300 K to 1150 K in nano silica. The different structural transitions, such as monoclinic, orthorhombic, orthorhombic with a non-integral super lattice, stable orthorhombic and hexagonal, which exist in silica are explained based on on-line high-temperature ultrasonic velocity and attenuation measurements