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Cobalt ferrite (CoFe2O4) ceramics were effectively synthesized using the co-precipitation method, followed by an investigation into the impact of sintering temperature on various properties including structure, morphology, magnetism, and dielectric behavior. These obtained ceramics exhibited a spinel ferrite structure with cubic symmetry. The average grain size increased from 0.26 to 0.83 μm, as the sintering temperature raised from 400 to 1000 °C. Dielectric measurements demonstrated significant temperature-dependent behavior across all frequencies, suggesting a pronounced influence on polarization within the ferrites, likely caused by localized electron displacement due to electronic exchange between Fe2+ and Fe3+ ions along the direction of the applied electric field. Analysis of impedance and modulus confirmed a negative temperature coefficient of resistance (NTCR) response. Additionally, the increase in ac conductivity with temperature was found to enhance charge hopping, resulting in decreased activation energy (Ea) for specimen mobility responsible for conduction. Magnetic properties exhibited enhancement with increasing sintering temperature, with maximum magnetization, coercivity, and remanent magnetization values increasing accordingly. However, non-saturation at high fields suggested surface effects in the CoFe2O4 ceramics. Notably, the CFO ceramic sintered at 1000 °C displayed a maximum magnetization value of approximately 74.54 emu/g at room temperature, while the highest coercivity value among all samples was 1368.33 Oe for the sample sintered at 900 °C. [ABSTRACT FROM AUTHOR]

The ceramic Sr(NiNb)0.5O3, incorporating silver doping in the A site, was synthesized using a sol–gel route and subjected to comprehensive analysis through various experimental techniques. X-ray diffraction data analysis indicates a rhombohedral crystal structure. Scanning electron microscopy (SEM) examination reveals densely packed grains with minimal surface porosity. A thorough investigation of electrical properties, encompassing dielectric constant, loss tangent, electrical impedance, modulus, conductivity, etc., was conducted across a wide frequency range (103–106 Hz) and temperature range (260–340 K). This analysis provided valuable insights into structure–property relationships and conduction mechanisms. The discussion highlights the significance of interface effects, space charge polarization, and Maxwell–Wagner dielectric relaxation in achieving the material's high dielectric constant at low frequencies and elevated temperatures. Examination of temperature dependence through Nyquist plots elucidates the contributions of grain behavior to the material's resistive and capacitive properties. The dielectric permittivity, dissipation of energy, and electrical characteristics like impedance, modulus and conductivity are notably influenced by the frequency of the applied electric field and temperature. Overall, the material exhibits promising potential for industrial applications such as energy storage, given its intriguing properties. [ABSTRACT FROM AUTHOR]

Motivated by the widespread applications of nanofluids, a nanofluid model is proposed which focuses on uniform magnetohydrodynamic (MHD) boundary layer flow over a non-linear stretching sheet, incorporating the Casson model for blood-based nanofluid while accounting for viscous and Ohmic dissipation effects under the cases of Constant Surface Temperature (CST) and Prescribed Surface Temperature (PST). The study employs a two-phase model for the nanofluid, coupled with thermophoresis and Brownian motion, to analyze the effects of key fluid parameters such as thermophoresis, Brownian motion, slip velocity, Schmidt number, Eckert number, magnetic parameter, and non-linear stretching parameter on the velocity, concentration, and temperature profiles of the nanofluid. The proposed model is novel as it simultaneously considers the impact of thermophoresis and Brownian motion, along with Ohmic and viscous dissipation effects, in both CST and PST scenarios for blood-based Casson nanofluid. The numerical technique built into MATLAB's bvp4c module is utilized to solve the governing system of coupled differential equations, revealing that the concentration of nanoparticles decreases with increasing thermophoresis and Brownian motion parameters while the temperature of the nanofluid increases. Additionally, a higher Eckert number is found to reduce the nanofluid temperature. A comparative analysis between CST and PST scenarios is also undertaken, which highlights the significant influence of these factors on the fluid's characteristics. The findings have potential applications in biomedical processes to enhance fluid velocity and heat transfer rates, ultimately improving patient outcomes. [ABSTRACT FROM AUTHOR]