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(NiO) x (Bi 1.6 Pb 0.4 )Sr 2 Ca 2 Cu 3 O 10-δ composite, where 0.0 ≤ x ≤ 0.2 wt%., were prepared using solid state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). Vickers microhardness measurements (H V ) were carried out at room temperature under different applied loads varying from 0.49 to 9.8 N, and dwell times (40 and 59 s). It was noted that dwell time and Vickers microhardness were inversely proportional. H V values increase as x increases up to 0.1 wt%, and then they decrease with further increases in x. All samples exhibit indentation size effect (ISE) with normal trend, as Vickers microhardness decreases by increasing the applied loads. Also, Vickers microhardness measurements of the prepared samples were done during both loading forces up to 9.8 N and unloading downwards to 0.49 N. It was noted that unloading values of Vickers microhardness are slightly greater than loading values. The elastic/plastic deformation model (EPD) was used to interpret the loading and unloading Vickers microhardness results. It is clearly noted that values of d o, the added elastic component the measured plastic indentation semi-diagonal (d),in the unloading results are much higher than those for loading data. The effect of liquid nitrogen immersion for 16 h on Vickers microhardness values was examined. A significant improvement in the Vickers microhardness of (Bi, Pb)-2223 samples immersed in liquid nitrogen was observed. Such behavior is attributed to the fact that nitrogen immersion increases the volume contraction of the superconductor matrix, causing the shrink of the pores and voids present in the samples. Different models were used to analyze the obtained results such as Meyer's law, Hays–Kendall (HK) approach, elastic/plastic deformation (EPD) model, and modified proportional specimen resistance (MPSR) model. The experimental results of Vickers microhardness of both samples without and with liquid nitrogen immersion are well fitted according to the MPSR model. [ABSTRACT FROM AUTHOR]

Highlights: [•] The effect of nanosized ZnFe2O4 on the Gd-123 phase was studied. [•] The phase formation and superconducting parameters were improved up to x =0.06wt.%. [•] The Vickers microhardness number increased as x increased. [•] The Vickers microhardness data agreed with the proportional specimen resistance model. [ABSTRACT FROM AUTHOR]

The co-precipitation method was adopted to synthesize Ni 1-x Ru x O nanoparticles, with x = 0.000, 0.005, and 0.010. The X-Ray Diffraction patterns showed the formation of the NiO phase without any secondary phases or impurities due to the doping. The Ru-dopants are well incorporated into the lattice without changing its structural properties, owing to the comparable ionic radii of Ru3+ and Ni2+ ions. The doped samples have cubic morphology with reduced sizes, as seen in Transmission Electron Microscope images. The Fourier Transform Infra-Red and X-Ray Photo-induced spectra (XPS) assured the purity and the successful doping of trivalent Ru ions into NiO nanoparticles. Moreover, the XPS spectra revealed the generation of more oxygen vacancies with Ru-doping. The optical properties were investigated by Ultra-Violet and Photoluminescence (PL) spectroscopies. The Ru-doped samples have higher transmittance that is beneficial for transparent electrodes and optoelectronic devices. The TAUC and derivative plots were used to estimate the bandgap energies. The Ru-doped samples demonstrated suppressed bandgap energies, mainly due to the formation of additional energy levels near the valence band. The visible region of the PL spectra was investigated to track the deep-level defects. All the samples have traces of nickel vacancies, oxygen vacancies, and oxygen interstitials. The magnetic studies were tested by Vibrating Sample Magnetometer at room temperature. The M − H loops were then fitted by the different models of the law of approach to saturation. The best-fitted model was the one accounting for the exchange and anisotropy fields. The pure and Ru-doped samples showed a weak ferromagnetic behavior with a slight increase in the linear magnetization with Ru dopants, due to the antiferromagnetic Ru–Ru interactions. • The co-precipitation method is implemented to synthesize Ru doped NiO nanoparticles. • The Ru dopants are well incorporated into the NiO lattice with 3+ oxidation state. • Ru dopants induced more oxygen vacancies in NiO nanoparticles, as detected by XPS. • Reduced energy gap with Ru dopants is achieved that is useful for optoelectronics. • Combination of ferromagnetic – antiferromagnetic nature is depicted in the samples. [ABSTRACT FROM AUTHOR]

Abstract: Superconducting samples of the type GdBa2Cu3− x Ru x O7− δ with 0.000⩽ x ⩽0.300 were prepared by the conventional solid-state reaction technique. The phase formation percentage, lattice parameters, orthorhombic distortion and oxygen-content were calculated using X-ray powder diffraction (XRD) data. The real elemental-content of the prepared samples was estimated from particle induced X-ray emission (PIXE). In addition, the oxygen-content was determined using elastic Rutherford backscattering spectroscopy (RBS) technique at 3MeV proton beam and Rietveld XRD analysis. Moreover, the prepared samples were investigated using electron paramagnetic resonance (EPR) measurements. The number of spins N participating in EPR resonance and the paramagnetic susceptibility χ were calculated as a function of both Ru-content and temperature. In addition, the activation energy Ea , Curie constant C, Curie temperature θ, the effective magnetic moment μ and the electronic specific heat coefficient γ were estimated as a function of Ru-content. [Copyright &y& Elsevier]

Abstract: This work studied X-ray powder diffraction (XRD), electrical resistivity and electron paramagnetic resonance (EPR) measurements for Bi1.8Pb0.4Sr2Ca2.1Cu3−x Ru x O10+δ (0.0≤ x ≤0.4) superconducting samples. XRD analysis and electrical resistivity data showed that the low-content of Ru, x ≤0.05, enhanced both the phase formation and the superconducting transition temperature of (Bi, Pb)-2223 phase. A phase change from (Bi, Pb)-2223 phase to (Bi, Pb)-2212 phase was reported for x ≥0.15. Two EPR lines were observed for 0.0≤ x ≤0.075, indicating the presence of both (Bi, Pb)-2223 and (Bi, Pb)-2212 phases. While, one EPR line was observed for x ≥0.15, corresponding to the (Bi, Pb)-2212 phase formation. The number of spins (N) participating in the resonance and its spin paramagnetic susceptibility (χ), for the two phases, were calculated as a function of both Ru-content and temperature. In addition, we reported the variation of activation energy (E a ), Curie constant (C), Curie temperature (θ) and effective magnetic moment (μ) with Ru-content. [Copyright &y& Elsevier]

ETHNOPHARMACOLOGICAL RELEVANCE: The Q'eqchi' Maya possess a large selection of plants to treat neurological disorders, including epilepsy and susto (fright), a culture-bound illness related to anxiety disorders. AIM OF THE STUDY: To investigate the activity of antiepileptic and anxiolytic plants in the GABAergic system, and determine if there is a pharmacological basis for plant selection. MATERIALS AND METHODS: Ethanol extracts of 34 plants were tested in vitro for their ability to inhibit GABA-transaminase (GABA-T) or bind to the GABA(A)-benzodiazepine (BZD) receptor, two principal drug targets in epilepsy and anxiety. Pharmacological activity was correlated with relative frequency of use, based on informant consensus. RESULTS: Ten plants showed greater than 50% GABA-T inhibition at 1mg/ml, while 23 showed greater than 50% binding to the GABA(A)-BZD receptor at 250 µg/ml. Piperaceae, Adiantaceae and Acanthaceae families were highly represented and active in both assays. There was a significant positive correlation between GABA-T inhibition and relative frequency of use for epilepsy, and an even stronger correlation between GABA(A) binding and relative frequency of use for susto (fright). CONCLUSIONS: Clearly, Q'eqchi' traditional knowledge of antiepileptic and anxiolytic plants is associated with the use of pharmacologically active plants. Based on the evidence, it is suggested that the mechanism of action for some traditionally used plants may be mediated through the GABAergic system. [ABSTRACT FROM AUTHOR]

Abstract: Bulk Tl0.8Hg0.2Ba2Ca2−x Sm x Cu3O9−δ superconducting samples with x =0.00, 0.025, 0.05, 0.10, 0.15, and 0.20 were prepared, in a sealed quartz tube, by a single step solid-state reaction technique. The prepared samples were investigated using X-ray powder diffraction, scanning electron microscope, electron dispersive X-ray, electrical resistivity, ac magnetic susceptibility and electron paramagnetic resonance. Powder X-ray diffraction analysis revealed that the prepared samples are nearly single phase of (Tl, Hg)-1223 with tetragonal structure (space group P/4mmm). The temperature dependence of the electrical resistivity and the ac magnetic susceptibility was investigated to study the effect of Sm-substitution, on the superconducting transition temperature T c and the intergrain critical current density J c. The data showed a T c suppress as Sm-content increases, whereas J c increases up to x =0.05, after that it depresses with further increase in x. Furthermore, electron paramagnetic resonance (EPR) spectrum at room temperature was studied for the prepared samples. The values of the gyromagnetic factors, g ⊥, g ∥, the hyperfine structure and the spin density were calculated as a function of Sm-content. [Copyright &y& Elsevier]

Abstract: The effect of nano-size MgO (40–60nm) addition on both granular structure and volume thermal expansion measurements of polycrystalline (Cu0.25Tl0.75)-1234 was studied. The MgO-content x varied from 0.0 to 1.0wt.% of the sample total mass. Granular investigation using scanning electron microscope revealed that both number and size of voids decreased as x increased from 0wt.% to 0.6wt.%. These results were supported by porosity calculation of the samples. The volume thermal expansion was calculated using X-ray powder diffraction from room temperature down to 80K. The volume thermal expansion coefficient, at room temperature decreased, from 9.3×10−5 K−1 to 7.2×10−5 K−1 as MgO-concentration increased from 0.0wt.% to 0.6wt.% before it increased to 8.9×10−5 K−1 for MgO-concentration=1wt.%. The Debye temperatures, calculated from the volume thermal expansion coefficient measurements, were reported as a function of MgO-concentration and superconducting transition temperature. [Copyright &y& Elsevier]

Abstract: Cu0.5Tl0.5Ba2Ca2−x Cd x Cu3O10−δ superconductor samples (x =0–0.8) were prepared by a single-step solid-state reaction technique in order to investigate the effect of Cd-substitution on the formation and the transport properties of the (Cu, Tl)-1223 phase. A nearly single-phase materials is synthesized with x =0.2 and found to have optimum superconducting transition temperature T c and critical current density J c. The dielectric constant and the loss tangent, for all the prepared samples, were measured at room temperature as a function of frequency up to 5MHz. The normal dielectric constant is strongly dependent on Cd-content and correlates with the normal electrical resistivity results. This correlation was discussed according to the grain boundaries scattering. [Copyright &y& Elsevier]

Abstract: A series of superconducting samples of type Tl0.8Hg0.2Ba2Ca2−x R x Cu3O9−δ, where R=Sm and Yb with , were prepared in a sealed quartz tube via a solid-state reaction technique. The electrical resistivity was measured as a function of temperature using the conventional dc four-probe technique. The fluctuation conductivity , above the superconducting transition temperature , was analyzed as a function of temperature using the Aslamazov and Larkin model. It exhibits five different fluctuation regions namely critical (cr), three-dimensional (3D), two-dimensional (2D), one-dimensional (1D) and short-wave (sw). The zero-temperature coherence length, the effective layer thickness of the two dimensional system, the wire cross-sectional area for one dimensional systems and the inter-layer coupling strength were estimated as a function of the substitution-content . Furthermore, the thermodynamics critical field, lower critical magnetic field, upper critical magnetic field, critical current density and Fermi energy are calculated from the Ginzburg number. [Copyright &y& Elsevier]

Abstract: The effect of partial replacement of copper by zinc in Tl2Ba2Ca2Cu3O10−δ superconductor phase is studied. Superconducting samples of the nominal composition Tl2Ba2Ca2Cu3−x Zn x O10−δ with x ranging from 0 to 0.6 are prepared under normal pressure by a one step of solid-state reaction technique. The samples are characterized by using X-ray powder diffraction, scanning electron microscope (SEM) and EDX. The X-ray data indicate that the partial replacement of Cu2+ions by Zn2+ions does not influence the tetragonal structure of the samples, and the lattice parameters a and c vary according to the difference in the ionic radii of Cu and Zn. The superconducting parameters, such as superconducting transition temperature T c, critical current density J c and irreversibility field B ir are calculated from electrical resistivity and AC-magnetic susceptibility measurements. [Copyright &y& Elsevier]

Abstract: The normal-state Hall effect for Tl0.8Hg0.2Ba2Ca2−x R x Cu3O9−δ, where R=Sm and Yb with , is measured above the superconducting transition temperature. The Hall coefficients , for all prepared samples, are positive and follow the Curie–Weiss temperature dependence type. Carrier-concentrations decrease as the substitution-content increases, as a result of the hole-filling mechanism. The sample with lower resistivity exhibits higher carrier-concentration. The Hall angle cot increases as the temperature increases and well fitted to the formula cot . The constant is found to be strongly dependent on the substitution-content and it is correlated to the residual resistivity . Finally, the variation of Hall mobility with both temperature and substitution-content is reported. [Copyright &y& Elsevier]

Abstract: Specific heat and thermopower measurements are carried out for a series of high-temperature superconductor samples of type with . The thermopower coefficient is measured as a function of temperature from room temperature down to liquid nitrogen temperature, 77 K, using a standard differential technique. The results are analyzed according to the two-band model (Fermi-liquid model) and the two-band model with an extra linear term. The specific heat is measured from room temperature down to 10 K using a physical property measurement systems (PPMS, Quantum Design). The specific heat data for all prepared samples do not show any discontinuity change at the superconducting transition temperature, indicating the high anisotropy of Tl-1223. The Debye temperature, calculated from the specific heat measurements, is temperature dependent and depends on the Na content. Finally, a relation between the Debye temperature and the superconducting transition temperature is reported to explain the suppression of superconductivity of Tl-1223 due to sodium substitution. [Copyright &y& Elsevier]

Abstract: Ion beam analysis techniques (IBA) were performed to determine the elemental stoichiometry of superconducting samples of type TlBa2Ca2− x Sc x Cu3O9− δ , with 0⩽ x ⩽0.6, prepared via solid-state reaction technique. By combining particle induced X-ray emission (PIXE) with Rutherford backscattering spectrometry (RBS), the stoichiometry of the samples is determined. However, the oxygen content is obtained by using non-Rutherford backscattering cross-section at 3MeV proton beam. Furthermore, the prepared samples were also characterized using X-ray powder diffraction (XRD) and electrical resistivity measurements. The X-ray data indicate that the partial substitution of Ca2+ by Sc3+ ions does not affect the tetragonal structure of Tl-1223 superconducting phase. The superconducting transition temperatures T c, determined from electrical resistivity measurements, was found to be highly correlated to the Sc-content. [Copyright &y& Elsevier]

In the attempt of producing multifunctional materials, the Sm3+ and Er3+ partial alternatives of Co in Co 3 O 4 nanoparticles were synthesized via the co-precipitation method with the chemical formula Co 3-2x Sm x Er x O 4 (0.00 ≤ x ≤ 0.06). The structural analysis by XRD revealed that x = 0.02 at.% is the maximum solubility of Sm and Er in the Co 3 O 4 matrix, which beyond it there are small traces of the Sm 2 O 3 secondary phase. The size of the nanoparticles, obtained from XRD and TEM, decreased with increasing the co-doping percentages, leading to an increase in the surface area, and hence, benefit the magnetic recording density and electron transport efficiency. Moreover, the co-doping changed the morphology from slightly agglomerated spherical-shaped nanoparticles to the highly agglomerated mixed morphology of welded nanorods and nanokernels. The tetrahedral and octahedral functional groups were revealed by FTIR spectroscopy, declaring the successful formation of Co 3 O 4 spinel structure. The UV–vis spectroscopy showed a monotonic decrease in the absorbance with increased codopants concentration accompanied by a widening of the band gap energy that serves photovoltaic materials, solar cells ... The defect concentrations were investigated by photoluminescence spectroscopy that assured the presence of cobalt interstitial as the main defect. The intensity is quenched with x = 0.01 at.%, addressing the heterogeneous photocatalysis, and enhanced to reach its maximum with x = 0.06 at.%, fostering the electrochemical supercapacitors. The concentration of these defects directly influences the magnetic behavior as proposed by the Bound Magnetic Polaron theory. The codopants render the nanoparticles softer magnetic materials due to the decrease in their coercivity and retentivity, which is good for data storage applications and electromagnetic materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Increasing laser power shifts the Raman modes and changes their intensities. • Increasing laser power decreases 1LO/2LO intensity ratio. • Laser probe heating effect, lattice expansion, and spin-phonon coupling contribute. • Different polarizations lead to slight intensity fluctuations in first phonon mode. The effect of laser heating on the Raman spectra of pure, (Mg, Cu), and (Mg, Ru) codoped NiO nanoparticles was analyzed. Laser power increase (0.15–4.52 mW) caused Raman shifts and intensity variations that indicated stoichiometry and microstructural deviations. Raman spectra of (Mg, Ru) codoped NiO nanoparticles indicated the presence of RuO 2 secondary phase. At higher laser power, peaks associated with phonon modes of secondary phases were eliminated. The laser power impacted the structure by expanding the lattice, reducing instability, and substituting Ru into the lattice. Polarization-dependent Raman measurements showed symmetrical nature and preferred crystallization orientation of each sample. [ABSTRACT FROM AUTHOR]

Oxide/ferrite nanocomposites are gaining great attention due to the induced exchange interactions between the different phases. Herein, the weak ferromagnetic MgFe 2 O 4 nano-ferrites are combined with antiferromagnetic Mn 1.95 Sn 0.05 O 3 nano-oxides, via co-precipitation and ball milling. The synthesized samples demonstrated the combination of ferrite and oxide phases, as confirmed by XRD analysis. This combination also generated two distinct morphologies and particle size distributions, as seen in TEM images. The SAED images depicted the polycrystalline nature of the samples. The XPS technique detected the spin-orbit doublets of the main spectral lines, revealing their different oxidation states. FTIR assisted the merged phases by the presence of multiple vibrational bands. The nanocomposites exhibited weak ferromagnetic nature, emerging from the uncompensated surface spins, as seen in M − H loops. Besides, the switching field distribution curves indicated the exchange coupling between the two phases. EPR spectra showed a decrease in g values as Mn 1.95 Sn 0.05 O 3 content increased. [ABSTRACT FROM AUTHOR]

The current study investigated the effect of adding yttrium iron garnet (Y 3 Fe 5 O 12 ; YIG) nanoparticles to the (Bi 1.8 Pb 0.4)Sr 2 Ca 2.1 Cu 3.2 O y ((Bi,Pb)-2223) superconductor. The classical solid-state reaction technique was used to synthesize the nano-(YIG) x /(Bi,Pb)-2223 composites (0.00 ≤ x ≤ 2.00 wt.%). X-ray diffraction (XRD) confirmed the formation of tetragonal (Bi,Pb)-2223 as the major phase. The morphology and elemental composition of the synthesized samples were investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), respectively. Iodometric titration analysis proved that the addition of nano-YIG increased the oxygen content in the CuO 2 planes. The critical transition temperature (T c) and the critical current density (J c) increased with the nano-YIG addition up to x = 0.25 wt.% with values of 119.25 K and 638.37 A/cm2, respectively. X-ray photoelectron spectroscopy (XPS) revealed the elemental composition and oxidation state of all elements in the prepared samples. Room temperature Vickers microhardness (H v) measurements were performed at different applied loads (0.49–9.80 N) and a duration time of 20 s. The best enhancement in Vickers microhardness (H v) was achieved at x = 2.00 wt.%. The modified proportional sample resistance (MPSR) model provided the best theoretical analysis at the plateau limit region based on Vickers microhardness (H v) observations. Moreover, nano-YIG addition into the (Bi,Pb)-2223 superconductor adversely affected several mechanical parameters such as the elastic modulus (E), yield strength (Y), and fracture toughness (K). [ABSTRACT FROM AUTHOR]

Samarium iron garnet, Sm 3 Fe 5 O 12 , co-doped with Gd3+ and Pr3+ ions, having the chemical formula Sm 3-2x Gd x Pr x Fe 5 O 12 (0.0 ≤ x ≤ 0.8), were synthesized by the co-precipitation method. The structural study confirmed the cubic crystallization of the Sm 3 Fe 5 O 12 phase in the addition of two secondary phases, α-Fe 2 O 3 and SmFeO 3. The variation of the lattice parameters and crystalline size indicated that both Gd3+ and Pr3+ ions were incorporated into the lattice. The elemental analysis confirmed the stoichiometry proposed for Sm 3-2x Gd x Pr x Fe 5 O 12. The co-doping process of SmIG affected the absorbance of photo-radiations, making them possible candidates for transparent electrodes and optoelectronic devices. Energy band gap values were in the range of 2.921–3.004eV. DC electrical conductivity measurements studied the transport properties through which two activation energies were determined. The co-doping process affected the dielectric constants (ε ′ , ε ″ , tan δ), which reached a maximum value for x = 0.2. Dielectric relaxation was observed in the measurements, which could be due to the presence of oxygen vacancies as detected in XPS results. The Nyquist plots revealed that all the samples exhibited a negative temperature coefficient of impedance, where the arc of the semicircles decreased as the temperature increased from 413 to 743K. Also, the contribution of the resistance at high-frequency was related to the grains and grain boundaries. The ac conductivity mechanism followed the small polaron and the correlated barrier hopping models. In the temperature range between 333 and 583K, the prepared samples are promising for ion-conducting glasses and ionic crystals. [ABSTRACT FROM AUTHOR]

• Full-scale real-time tests of a double liner system long-term performance. • Failure of geotextile components of GCL and GCD in 6 years at 85 °C and 250 kPa. • Demonstration that design can finesse problems due to geotextile degradation. • Demonstrates importance of service life all components of double liner systems. The long-term performance of a geosynthetic clay liner (GCL) above a drainage layer and a geocomposite drain (GCD) are investigated. Full-scale tests are used to: (i) assess the integrity of GCL and GCD in a double composite liner below a defect in the primary geomembrane with ageing, and (ii) establish the head at which there was internal erosion in GCL without a carrier geotextile (GTX) such that the bentonite is in direct contact with the underlying gravel drainage. Six years after contact with simulated landfill leachate at 85 °C through an intentional defect on the geomembrane, the GCL resting on the GCD had failed due to degradation of the GTX between the bentonite and the core of the GCD and subsequent erosion of the bentonite into the core structure of the GCD was observed. In addition to complete degradation of its GTX at some locations, the GCD had also experienced extensive stress cracking and rib rollover. The second test demonstrates that if a suitable gravel drainage layer had been used instead of the GCD, the GTX component of the GCL would not have been required for acceptable long-term performance under normal design conditions and indeed could withstand a head of up to 15 m before problems became evident. The findings serve as a warning landfill designers and regulators that more attention must be paid to the service life of all components of double liner systems used in Municipal Solid Waste (MSW) landfills. [ABSTRACT FROM AUTHOR]

This study investigates the synthesis of Ni 1–2x Gd x Ru x O nanoparticles, with different concentrations of Gd and Ru dual dopants, in an attempt to improve their dielectric and electrical properties. These samples are synthesized via the co-precipitation method, and characterized by various structural, methods, including the X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM), and Raman spectroscopy. The XRD patterns demonstrated the formation of single NiO phase, revealing the good incorporation of (Gd, Ru) in NiO lattice. The crystallite size decreased from 21 to 10 nm with increasing the dual dopants' concentration. The TEM images demonstrated pseudo-spherical morphology of the Ni 1–2x Gd x Ru x O nanoparticles and the Raman spectra detected the fundamental vibrational modes of NiO. The frequency and temperature-dependent dielectric constants were augmented by the incorporation of the dual dopants, due to the induced nickel vacancies and larger surface-to-volume ratio. The Nyquist plots demonstrated depressed semicircles with smaller radii as the temperature and the dual dopants' concentration increased. This was related to the enhancement of ac conductivity that followed different trends at room and high temperatures. The ac conductivity was tuned by varying the dual dopants concentration due to the ionic compensation mechanism, and the changes in the charge carriers' concentrations and mobility. The correlation between the different dielectric and electric parameters suggested the dominance of the long-range conduction of the charge carriers. [Display omitted] • Ni 1−x Gd x Ru x O nanoparticles, with x = 0–0.02, were prepared by co-precipitation method. • Gd and Ru dual dopants improved the dielectric properties of NiO nanoparticles. • Parallel RC circuits fitted the Nyquist plots with less R for higher dual dopants. • AC conductivity increased with dual dopants that were ionically compensated in NiO. • Gd and Ru dual dopants increased the interest in NiO for electronic applications. [ABSTRACT FROM AUTHOR]

Vickers microhardness measurements of Y 3−x Nd x Ba 5−x Ca x Cu 8 O 18−δ samples, 0.00 ≤ x ≤ 0.40, were carried out at room temperature at different applied loads varies from 0.25 N to 10.00 N. Vickers microhardness decreases as the substitution content increases, as well as it decreases as the applied loads increase. The results were analyzed using different models such as Meyer's law, Hays–Kendall (HK) approach, elastic/plastic deformation (EPD) model, proportional specimen resistance (PSR) model and modified proportional specimen resistance (MPSR) model. The analysis shows that the MPSR model is the most suitable one to describe the load independent microhardness for Y 3−x Nd x Ba 5−x Ca x Cu 8 O 18−δ superconducting samples at high load. Some important mechanical parameters such as Young's modulus ( E ), yield strength ( Y ), fracture toughness ( K f ) and brittleness index ( B i ) were calculated as a function of substitution content. The results show that they decrease by increasing the substation content for Y 3−x Nd x Ba 5−x Ca x Cu 8 O 18−δ samples. [ABSTRACT FROM AUTHOR]

This study investigates the optical and magnetic properties of nanosized (x)NiO/(1−x)CdFe 2 O 4 (x = 0.1, 0.2, 0.3, 0.4, 0.5, and 1) composites. The samples were synthesized using the wet coprecipitation technique. The X-ray Diffraction patterns demonstrated the formation of Nickel Oxide (NiO) and Cadmium Ferrite (CdFe 2 O 4) phases without any chemical reaction between them. Fourier Transform Infrared results confirm the formation of pure NiO, pure CdFe 2 O 4 , and nanosized NiO/CdFe 2 O 4 composites. Transmission Electron Microscopy micrographs show agglomeration between the nanoparticles, demonstrating the magnetic interaction between the oxide and ferrite phases. High-Resolution Transmission Electron Microscopy results verify the presence of NiO and CdFe 2 O 4 phases in each nanosized composite without impurities, which is consistent with the XRD data. The ultraviolet–visible spectroscopy results confirmed that HCl is a better solvent than ethanol in investigating the optical properties of nanosized oxide/ferrite composites. Photoluminescence spectra exhibited asymmetricity owing to the presence of various emission peaks, which reveals the distribution of defect states within the bandgap of the nanosized composites. The Mössbauer spectra of the nanosized composites comprised an asymmetrical doublet at 300 K and an asymmetrical centered doublet within minor sextets at 77 K. Vibrating Sample Magnetometer study showed a shift at 77 K, which can be attributed to the spontaneous exchange bias effect. The magnetic parameters extracted from the M − H loops of all the synthesized nanosized composites at 77 K are higher than those at 300 K. [ABSTRACT FROM AUTHOR]

Nanocomposite (x)NiO/(1-x)CdFe 2 O 4 were synthesized using co-precipitation method with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1. The X-ray diffraction patterns reveal the presence of NiO and CdFe 2 O 4 phases with no chemical reaction between both phases. The scanning electron microscope images show the agglomeration between the particles, revealing the magnetic interaction between NiO and CdFe 2 O 4 nanoparticles. The band-gap energy E g , measured from UV–vis spectra, decreases with the increase of the particle size measured from the transmission electron microscope. The obtained data from the vibrating sample magnetometer indicate that NiO and CdFe 2 O 4 nanoparticles are interacting magneto-statically. The coercivity and the saturation magnetization values of the nanocomposites are found to be in the ranges 3.22–378.62 G and 0.27–2.34 emu/g respectively. Exchange couple interaction between NiO and CdFe 2 O 4 is confirmed from the single peak observed in switching field distribution curves. • The spinel cubic structure of CdFe2O4 nanoparticles and the fcc structure of NiO nanoparticles are confirmed by XRD. • TEM shows agglomeration of nanoparticles due to strong magnetic interaction between NiO and CdFe2O4. • The variation of the band gap energy with the particle size referred to the quantum confinement effect. • The switching field distribution curves indicate the exchange coupling interaction due to the observed single peak. [ABSTRACT FROM AUTHOR]

The preparation and characterization of novel nanocomposites (NCs) (1-x)Ni 0.5 Zn 0.5 Fe 2 O 4 /(x)Zn 0.95 Co 0.05 O, where x = 0.1, 0.2, 0.3, 0.4 and 0.5, is presented in the current investigation. The synthesis of NCs with high purity and crystallinity was confirmed by X-ray powder diffraction (XRD) measurements. Furthermore, the morphology of the NCs was examined using a transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM) analysis. The synthesis of well-dispersed spherical nanoparticles with a size range of 27–34 nm was confirmed. The investigation of the optical properties, by using UV–vis and photoluminescence (PL) spectroscopies, has shown a dependence of the energy bandgap and the PL intensity on the amount of Zn 0.95 Co 0.05 O. Additionally, X-ray photoelectron spectroscopy (XPS) was used to investigate the elemental composition and oxidation states of the elements forming the nanocomposites. Furthermore, M − H loop studies have shown that all NCs possess a soft ferromagnetic behavior with a single magnetic phase. The saturation magnetization was found to decrease with x. Several magnetic parameters including the retentivity, coercivity, magneton number, and anisotropy field are determined and discussed in correlation with the structural and optical properties. This magneto-optical investigation suggests the utilization of (1-x)Ni 0.5 Zn 0.5 Fe 2 O 4 /(x)Zn 0.95 Co 0.05 O NCs as a possible candidate for photocatalytic applications. [ABSTRACT FROM AUTHOR]

• Preparation of Bi3+ substituted BaFe 12 O 19 nanoparticles. • Enhancement of the saturation magnetization and maximum energy product. • Reduction of the coercivity in correlation to variations of crystallite size. • Applications in permanent magnets and magnetic recording devices. Ba 1 - x Bi x Fe 12 O 19 nanoparticles (0 ≤ x ≤ 0.1) were prepared by the chemical co-precipitation method. The structure and morphology of the samples were revealed using powder X-ray diffraction (XRD) and transmission electron microscope (TEM). Both XRD and TEM confirm the synthesis of hexagonal Hexaferrites in the nanoscale, with average crystallite size in the range of 16.5–41.2 nm. Moreover, the octahedral ion-oxygen and tetrahedral ion-oxygen vibration bands were detected by FTIR analysis. Furthermore, the hard magnetic properties of the ferrimagnetic nanoparticles were investigated by analyzing room temperature magnetic hysteresis (M –H). Bi3+ substitution has caused an enhancement in the saturation magnetization by 20% and a reduction in the coercivity field by 50% relative to the pure sample. The maximum energy product (BH) max was enhanced by 37%. The effective crystalline isotropy constant and the anisotropy field showed an increase with Bi3+ substitution. The changes in the magnetic parameters are correlated to the changes in the structural parameters induced by Bi3+ substitution. [ABSTRACT FROM AUTHOR]

Herein, low-cost chloride precursors, EDTA, and NaOH were employed through a facile coprecipitation synthesis route to prepare pure and codoped NiO nanoparticles: Ni 1–2x Mg x M x O, where M = Cu and Ru and x = 1, 4, and 8 at%. To examine the impact of reaction temperature on the thermal, structural, morphological, optical, and magnetic properties of the prepared samples, the precursor aqueous solutions were heated at 60, 70, and 80 ºC. Data analysis revealed the strong dependence of all the studied properties on reaction temperature and codoping. Thermogravimetric analysis (TGA) was performed to evaluate the thermal stability of the prepared samples. The face-centered cubic (fcc) crystallization of NiO was maintained at all the applied temperatures and doping concentrations. X-ray diffraction (XRD) patterns showed the good incorporation of Mg2+ and Cu2+ ions with the host Ni2+ ions in Ni 1–2x Mg x Cu x O samples, while peaks of RuO 2 appeared as an impurity phase in Ni 1–2x Mg x Ru x O samples. Tiny spherical nanoparticles with a crystallite size of 6 nm were produced at 80 ºC and 8 at% (Mg, Ru) codoping. Energy dispersive X-ray (EDX) analysis confirmed that the elemental compositions of the synthesized samples were in stoichiometric ratios. The UV-Vis spectra demonstrated a monotonic increase in band gap with reaction temperature and codoping. The estimated Herve-Vandamme refractive index (n HV), the high (ε ∞) and the static (ε o) dielectric constants showed a decreasing trend with increasing reaction temperature. Weak ferromagnetic behavior was observed for the pure NiO samples, while the codoped samples with x > 4% showed linear M-H curves. The coercivety (H c) decreased with reaction temperature, implying single-domain magnetization and sizes below the critical one. The magnetocrystalline anisotropy (K) indicated the softness of the prepared samples. • NiO synthesized at different coprecipitaion reaction temperatures: 60, 70 and 80 ºC. • Crystallite size declined from 25 nm (NiO) to 6 nm (Ni 0.86 Mg 0.08 Ru 0.08 O). • Band gap energy widened from 3.51 eV (NiO) to 3.72 eV (Ni 0.86 Mg 0.08 Ru 0.08 O). • Reaction temperature increased the band gap energy and the maximum magnetization. [ABSTRACT FROM AUTHOR]

In the current study, nanoparticles (NPs) with Zn 0.33 Co 0.33 Mg 0.33 Fe 2 O 4 (F), Zn 0.33 Co 0.33 Mg 0.33 Cr 2 O 4 (C), and Zn 0.33 Co 0.33 Mg 0.33 Al 2 O 4 (A) were used to prepare various nanocomposites (NCs). Different NCs 0.5 F / 0.5 C (FC), 0.5 F / 0.5 A (FA), 0.5 A / 0.5 C (AC), and 0.33 F / 0.33 A / 0.33 C (FAC) were prepared via the co-precipitation method followed by the ball milling technique, starting from F, A, C (NPs). X-ray diffraction confirms the formation of NCs with minor impurities with cubic spinel structures. The transmission electron micrographs display the nearly spherical and cubic shapes of FC, AC, and FAC NCs. However, the FA nanocomposite (NC) has a nearly spherical shape. The elemental contents for NCs are confirmed using energy-dispersive X-ray spectroscopy. The existence of the vibrational modes of NPs, constituting each NCs, is verified by Fourier transform infrared spectroscopy. The bandgaps for various NCs, determined from ultraviolet-visible spectroscopy, are related to the crystallite size variations X-ray photoelectron spectroscopy results confirm the elemental composition as well as the oxidation states of the elements present in the NCs. M-H loops, measured by the vibrating sample magnetometer demonstrate a soft ferromagnetic behavior. The saturation magnetization M s for FA is higher than that of FC, AC, and FAC. The antibacterial activity of the synthesized NCs against four bacterial strains (Staphylococcus aureus, Stenotrophomonas maltophilia, Escherichia coli, and Enterococcus faecium) was evaluated by means of broth microdilution assay, minimum bactericidal concentration (MBC), and time-kill test. The synthesized NCs displayed different impacts against the targeted bacteria due to several factors, including size, shape, doping, secondary phase, optical, and magnetic parameters. These findings emphasize the potential application of these NCs in treating bacterial infections, including multidrug-resistant bacterial infections. [Display omitted] • Various (Zn, Co, Mg) ferrite, chromite and aluminate nanocomposites were successfully prepared. • Structural, morphological, optical and magnetic characteristics confirmed the formation of nanocomposites. • The nanocomposite containing ferrite, chromite and aluminate was more effective against bacteria. • Tri-spinel ferrite, chromite and aluminate nanocomposites provided more significant properties. [ABSTRACT FROM AUTHOR]

The Y 3-x Gd x Fe 5-y Mn y O 12 (x = y = 0.0, 0.2, 0.4, 0.6, 1.0, and 1.5) powders were synthesized by a co-precipitation method. The structural analysis confirmed the presence of the cubic structure of YIG, the formation of the secondary phase YFeO 3 and the stoichiometry proposed for Y 3-x Gd x Fe 5-y Mn y O 12. The results of the FTIR spectroscopy show three prominent absorption bands that shift to lower wavenumber values with the increase of co-dopant concentrations. Energy bandgap values are found to be 2.96 eV for pure YIG and 3.02 ± 0.1 eV for doped powders. Photoluminescence spectra show that all the samples exhibit intense peaks around 530 nm. Moreover, Gd3+ and Mn2+ partial alternatives strongly influence the magnetic behavior of YIG nanoparticles. It is observed that coercivity is affected by the crystallite size of 0.0 ≤ x = y ≤ 0.6, confirming the multidomain nature of the powders, which could be acceptable in microwave applications and data storage uses. [ABSTRACT FROM AUTHOR]

• These are the corrected Enhancement of the superconducting properties by the addition of nanoparticles. • The conduction mechanisms of electronic devices are functions of different parameters. • High dielectric constant materials show an important role in technological applications. Co-precipitation and solid-state reaction techniques were used to synthesize BaFe 12 O 19 nanoparticles and (BaFe 12 O 19) x (Bi,Pb)-2223 superconducting samples, with 0.00 ≤ x(wt%) ≤ 1.5, respectively. Hard ferromagnetic BaFe 12 O 19 nanoparticles had hexagonal structure with an average size of 63 nm. The structure of the superconducting samples reveal that the added nanoparticles settled at the grain boundaries without altering the host structure superconductors. The elemental composition of the samples is investigated using proton induced X-ray emission. The superconducting transition temperature (T c) and the critical current density (J c) were enhanced up to x = 0.5 wt%. The maximum values of dielectric properties of (BaFe 12 O 19) x (Bi,Pb)-2223 were found at lower frequencies and higher temperatures. [ABSTRACT FROM AUTHOR]

In this work, pure and 2% rare earth elements RE (RE = Y and Gd) doped NiO nanoparticles, capped with polyvinyl alcohol PVA, were prepared by coprecipitation technique. X-ray powder diffraction XRD was performed to investigate the structural properties of the prepared samples. X-ray peak profile analysis was carried out using the Debye Scherrer model DSM, the Williamson Hall WH approach by its three models: Uniform Deformation model UDM, Uniform Deformation Stress model UDSM and Uniform Deformation Energy Density model UDEDM, and using the size-strain plot SSP. It was found that doping NiO with both Y and Gd causes a decrease in the lattice parameter, lattice strain and crystallite size. Transmission Electron Microscopy TEM was done to study the particles size and morphology. The particle size trend obtained from the TEM images were agreeable with the crystallite size obtained from the XRD results. The TEM images showed homogeneous, nearly spherical and slightly agglomerated NiO nanoparticles, that can be good candidates for rechargeable Lithium ion batteries. Dielectric measurements were done by measuring the parallel-equivalent circuit mode capacitance C p , the dielectric loss tangent D (tanδ), the impedance Z and the impedance phase angle θ. Then, the frequency and temperature dependence of the dielectric constant ε', dielectric loss ε", loss tangent, ac conductivity σ ac and the imaginary part of both impedance Z″ and modulus M" were calculated and studied. Furthermore, the Nyquist plot was studied to correlate the electrical behavior by the microstructural contributions. The ionic radius and the valency of the dopant elements were found to be the factors that affect the dielectric behavior of the prepared samples. The dopant having larger ionic radius and higher valency was found to result in a higher dielectric constant and ac conductivity and a lower dielectric loss and electrical impedance, enhancing the role of NiO nanoparticles in electrical technologies, such as solar cells. • Pure and rare earth elements RE doped NiO nanoparticles, capped with PVA, were prepared. • Dielectric properties are found to be dependent on the ionic radius and the valency of the dopant element. • Gd and Y are considered as successful candidates for enhancing the dielectric properties of NiO nanoparticles. • The prepared nanoparticles are useful for solar cells and energy storage applications. [ABSTRACT FROM AUTHOR]

Pure and (Mg, Cu) codoped NiO nanoparticles were prepared via the co-precipitation method. The prepared nanoparticles were investigated by XRD, TEM, SEM-EDX, XPS, FTIR, Raman, UV–vis, PL and VSM. NiO cubic structure forms with no impurities or secondary phases. (Mg, Cu) codoping of NiO lowers its crystallite size and causes variation in the Ni stoichiometry as well as formation of O vacancies. The optical transmittance is enhanced up to 87% for x = 0.08, becoming beneficial for transparent electrodes. The bandgap and Urbach energies increase from 3.51 to 3.66 eV and 0.43–0.54 eV, respectively, whereas the optical dielectric constant decreases from 7.72 to 7.25 with enhancement of the electron-phonon interaction. Weak ferromagnetic contribution exists, and the ferromagnetic origin is explained by the BMP model. Coercivity and saturation magnetization decrease from 438.42 to 30.12 Oe and 0.267 to 0.178 emu/g, respectively, which is beneficial for data storage applications. • Mg and Cu were codoped successfully in NiO nanoparticles by coprecipitation method. • Optical transmittance, bandgap energy and electron-phonon interaction were enhanced. • Weak ferromagnetism was modified by codopants' concentration and surface effects. • (Mg, Cu) codoping was found beneficial in optoelectronic and data storage devices. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • NiO doped by different transition elements nanoparticles were successfully prepared by chemical co-precipitation method. • Ferromagnetic behavior was observed for different doped NiO nanoparticles. • The optical band gap was strongly dependent on the doped transition element type. • These nanoparticles can be useful for biomedical applications. Abstract Pure and 2% Mn, Fe and Zn doped NiO nanoparticles were synthesized by co-precipitation method at calcination temperature 550 °C. They were characterized by X-ray powder diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, proton induced x-ray emission, Rutherford Back Scattering, Fourier transmission infrared spectroscopy, UV-vis spectroscopy, M-H loop and electron paramagnetic resonance. The obtained results indicate that the lattice parameter, crystalline size, direct energy gap and chemical functional group are significantly dependent on the kind of dopant element. Moreover, the dopant elements are not affected by the ferromagnetic nature of NiO nanoparticles while g-factor varies according to the kind of dopant elements. [ABSTRACT FROM AUTHOR]

The influence of single wall carbon nanotubes SWCNTs and multi wall carbon nanotubes MWCNTs on Vickers microhardness of Gd-123 superconducting phase is studied. Samples of type (SWCNTs) x and (MWCNTs) x GdBa 2 Cu 3 O 7−δ , composite where, 0.0 ≤ x ≤ 0.1 wt.%, are prepared by solid-state reaction technique. The samples are characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM). Moreover the samples are examined by measuring electrical resistivity and Vickers microhardness. The obtained results showed an enhancement in the phase formation and grains connectivity up to 0.06 and 0.08 wt.% for SWCNTs and MWCNTs added samples, respectively. Likewise the superconducting transition temperature T c was improved at a low content of CNTs but it suppressed for higher concentrations. In addition, the analysis of Vickers microhardness measurements suggests that the most suitable model that describes the behavior of our sample is proportional specimen resistance PSR model. [ABSTRACT FROM AUTHOR]

Superconducting samples of SmBa 2 Cu 3 O 7− δ (Sm-123) added with various amounts of nanosized MnFe 2 O 4 addition (0.0−0.20 wt%) were investigated. The investigated samples prepared by the solid-state reaction method. The phase formation and microstructure of these samples were examined using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), proton induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS). XRD data indicate that the volume fraction of Sm-123 increases as nanosized MnFe 2 O 4 increases up to 0.02 wt%. The elemental distribution and oxygen content were deduced from PIXE and RBS. The oxygen content slightly decreases as MnFe 2 O 4 wt% increases. The superconducting transition temperature ( T c ) and critical current density ( J c ) of the prepared samples were estimated from electrical resistivity and transport critical current density measurements. It was found that T c decreases as nanosized MnFe 2 O 4 addition increases, while J c enhances up to 0.02 wt%. Moreover, the temperature dependence of normal state electrical resistivity was studied in view of the pseudogap opening in order to determine the pseudogap temperature T * as a function of nanosized MnFe 2 O 4 addition. T * increases as nanosized MnFe 2 O 4 increased, indicating the enhancement of the pseudogap formation in HTSCs by adding magnetic impurities. The crossover to fluctuation conductivity near the T c is discussed. [ABSTRACT FROM AUTHOR]

• Synthesis of nanocomposite via co-precipitation and ball milling methods. • BaSr/10%NiZn nanocomposite manifested optimum properties. • Weak exchange coupling and dominant dipolar interactions with the addition of NiZn. • The greatest value of the maximum energy product was registered as 22.89 kJ/m3. [Display omitted] In this work, magnetic nanocomposites Ba 0.5 Sr 0.5 Fe 12 O 19 /x(Ni 0.5 Zn 0.5)Fe 2 O 4 with the compositions x = 10, 20, 30, and 50 wt%, arising from nickel-zinc ferrite added to barium strontium hexaferrite were prepared and characterized. The samples were synthesized using co-precipitation and ball milling methods. X-ray powder diffraction measurements validated the synthesis of nanocomposite with high purity and crystallinity. A transmission electron microscope was also used to analyze the morphology of the nanocomposites that demonstrated hexagonal platelet-like and spherical-like shapes for hard and soft phases, respectively. Also, multiple shapes of different grain sizes were formed, and their grain size decreased upon the addition of the soft phase. Besides, the elemental compositions and the oxidation states of (Ba2+, Sr2+, Ni2+, Ni3+, Zn2+, Fe2+, Fe3+and O2-) constituting the nanocomposites were investigated, using X-ray photoelectron spectroscopy. Additionally, the magnetic properties were examined using a vibrating sample magnetometer. According to Henkel plots, the existence of a weak exchange coupling interaction and the dominance of dipolar interactions were visible upon the addition of Ni 0.5 Zn 0.5 Fe 2 O 4. Furthermore, the maximum energy product, (BH) max , is the energy density that a hard ferrite can store with low magnetic anisotropy. (BH) max of the nanocomposite containing 10 wt% of soft phase increased by 10% when compared to pure hard phase, reaching the highest value of (BH) max equal to 22.89 kJ/m3. [ABSTRACT FROM AUTHOR]

Abstract: In this work, superconducting samples of type (Cu0.5Tl0.5)-1223 added by nano-SnO2 (0.0–1.0wt.%) were prepared by solid-state reaction technique. The prepared samples were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS) for phase analysis and microstructure examination, respectively. Room temperature microhardness measurements were carried out at different applied loads (0.49–2.94N) for studying the performance of the mechanical properties of the studied samples. Furthermore, the experimental results of microhardness measurements were analyzed using different models in order to show the effect of nano-SnO2 addition on microhardness and elastic modulus. [Copyright &y& Elsevier]

This comparative study sheds light on the optimum addition x of K 5 [SiFe(OH 2)W 11 O 39 ]·14H 2 O ({FeSiW 11 }) and K 6 [(H 2 O)MnSiW 11 O 39 ]·21H 2 O ({MnSiW 11 }) (x = 0.02, 0.04, 0.08, 0.12, 0.16 and 0.20 wt%) nanoparticles to produce the desired mechanical characteristics of the (Bi,Pb)-2223 superconducting phase using a Vickers microhardness (H V) tester. H V measurement was performed at room temperature for different applied loads (0.245–9.8 N) and times (10–60 s). From the H V measurements, all the prepared samples had a normal 'indentation size effect' behaviour. It was found that 0.04 wt% {FeSiW 11 } nanoparticles and 0.08 wt% {MnSiW 11 } nanoparticles were the optimal addition to increase the microhardness of the (Bi,Pb)-2223 phase. Accordingly, other mechanical parameters for potential applications, such as the elastic modulus, yield strength and fracture toughness of the samples studied, were extracted from H V as a function of nanoparticle addition. The measured H V data were theoretically analysed with use of different models. The modified proportional sample resistance model was identified as the best theoretical model to describe the true H V values for both phases. Indentation creep analysis was also performed using time-dependent microhardness to indicate the enhancement of new cavity formation in the measured samples. • The Vickers microhardness of new polyoxometalate–(Bi,Pb)-2223 composites was studied. • The Vickers microhardness was increased by addition of both polyoxometalates. • All measured samples exhibit normal indentation size effect behaviour. • The experimental data are well fitted by the modified proportional sample resistance model. • Enhancement of new cavity formation was implied from indentation creep analysis. [ABSTRACT FROM AUTHOR]

In this paper, the effect of (Sm, Co) co-doping on the structure, optical and magnetic properties of ZnO nanoparticles was studied. Pure ZnO and (Sm, Co) co-doped nanoparticles, Zn 1-2x Sm x Co x O with x = 0.00, 0.005, 0.01, 0.02, 0.04 and 0.06, were synthesized by co-precipitation technique. The X-rays diffraction (XRD) scans were performed with 2θ varies from 20° to 80°.The XRD patterns of all samples confirmed the formation of wurtzite-type structure of ZnO with the formation of Sm 2 O 3 and Co 3 O 4 as minor secondary phases with x ≥ 0.005. The spherical morphology of pure ZnO is transformed to nanorods as the concentration of Sm3+ and Co2+ increases. The diameter and length of the nanorods were nearly 35.1–66.5 nm and 136.2–596 nm, respectively. UV–vis spectra were used for the calculation of the energy band gap (E g) by different methods. E g is found to increase with increasing (Sm, Co) doping up to x = 0.02. Energy band gap and Urbach energy are observed to have a reverse trend. Magnetic properties were investigated by the vibrating sample magnetometer. M − H hysteresis analysis reveals that for small doping, the samples have a ferromagnetic signal combined with diamagnetic contribution. The enhancement in ferromagnetism behaviour for 0.01 < x < 0.02 was justified by the formation of Bound Magnetic Polarons (BMPs) as it significantly enhances with the doping of Sm and Co by stabilizing Zn vacancy and other magnetic defects. Then the ferromagnetism is reduced for the doped samples up to x = 0.06, and an antiferromagnetic alignment is displayed. [ABSTRACT FROM AUTHOR]