Investigation of the magnetic characteristics of Cr-Zn and Cr-Co nanoferrite systems M. Lakshmi, P. Sarah Materials Research Innovations, 2025 The present investigation compares the effect of Cr3+ ion concentration on the magnetic characteristics of Crx Zn Fe2−x O4 and Crx Co Fe2−x O4 (0.0 ≤ x ≤ 0.5). The investigation on various magnetic characteristics was conducted using Vibrating Sample Magnetometer (VSM) under an external magnetic field of ± 15 kG. The measurements were conducted at room temperature. In the Cr-Co ferrite system, saturation in the M-H loop was achieved, whereas it was not obtained in the Cr-Zn ferrite system. Additionally, coercivity and remanent magnetisation exhibited non-linear behaviour with increasing Cr content (x) in both systems. In the current study, CrxZnFe2-xO4 (x = 0.3) and CrxCoFe2-xO4(x = 0.1) ferrite samples were found to possess very low coercivity values. The low coercivity makes these nanoferrites useful for soft ferrite applications. According to VSM reports, Cr3+ ion doping has significantly altered the magnetic characteristics of both Zinc and Cobalt ferrite systems.
Intelligent solutions for E-Waste Management using IoT and Public Awareness R. Kalyani, M. Lakshmi, P. Sarah, P. Durga Jaya Ram, Lalitha Bai K, K. Sunithaa Icrteect 2025 2nd International Conference on Recent Trends in Electrical Electronics and Computing Technologies, 2025 Management of electronic waste (e-waste) has emerged as a significant environmental issue, with improper disposal contributing to pollution and the depletion of valuable resources. A recent survey was conducted to assess public awareness, disposal habits, and perceptions regarding e-waste recycling. The results reveal that a notable percentage of participants (29.7%) opt to sell their old electronics, while 34.6% choose to store them; however, only 10.3% engage in active recycling. These findings highlight the need for better awareness campaigns and improved e-waste collection systems. Based on this problem, we are going to present a new design for the water flow level indicator using components from repaired e-waste. This system uses these disposed batteries to charge a solar panel and then use the energy to run a Node-MCU-based smart monitoring system to help better manage water. Not only does this method provide a sustainable solution towards conservation of resources, but it also demonstrates the exact applicability of e-waste. The approach involves the design of an arrangement with water level sensors, the incorporation of an energy-saving Internet of Things (IoT) system, and the renewal of energy storage using upcycled batteries. Tests carried out have proved the effectiveness of this technology, namely the ability of the system to detect water levels and to use the energy efficiently. The research underlines the sustainability of e-waste reuse in terms of introducing cost-effective and ecological solutions and also it advocates for public awareness and policy reforms
Investigation of the Dielectric Characteristics of Chromium-substituted Zinc and Cobalt Nanoferrite Systems M. Lakshmi, K. Sreelalitha, P. Sarah, B Samba Sivaiah, D. Naveen Journal of Physics Conference Series, 2024 The series of Cr-substituted Zn and Co nanoferrite systems having the chemical composition CrxZnFe2–xO4 and CrxCoFe2–xO4 (0.0 ≤ x ≤0.5) were prepared by sol–gel technique. The present investigation aims to compare the impact of Cr3+ concentration on dielectric characteristics of Zn and Co-nanoferrite systems. The investigation of various dielectric characteristics was conducted using an LCR meter at 1kHz frequency and across the frequency range of 100Hz to 1MHz. The measurements were conducted at room temperature. In the case of both ferrite systems, the plots of frequency Vs dielectric constant (ε′) and AC conductivity (σac) show a common dielectric behavior of spinel ferrites. The plots of frequency Vs dissipation factor (D) of Cr- Cr-substituted zinc and Cobalt nanoferrite samples were observed to be unusual and display a relaxation peak at a particular frequency. In the current study, CrxZnFe2-xO4(x=0.2 and 0.3) and CrxCoFe2–xO4 (x=0.3) ferrite samples were found to exhibit very high values of dielectric constant. So these ferrites may be useful for a wide range of applications in electrical storage devices. According to LCR reports, all the Cr3+ substituted ferrite samples in both ferrite systems exhibit higher dielectric constant and AC conductivity values. Possible mechanisms that may be accountable for the outcomes are thoroughly scrutinized in this paper.
Structural, microstructural, dielectric and ferroelectric properties of Ho3+ doped SrBi4Ti4O15 ceramics G. Rajashekar, T. Sreekanth, Srinivas Pattipaka, P. Sarah Ferroelectrics, 2022 The present work investigates microstructural, structural, ferroelectric and dielectric properties of Holmium, Ho3+, doped SrBi4Ti4O15 (SBT). Polycrystalline ceramics (SrBi4-xHoxTi4O15 SBHT, where x = 0, 0.02. and 0.03) were prepared by solid-state reaction method using high energy planetary ball mill. The surface morphology of all samples displayed dense microstructure and average grain size decreased with Holmium content increase. The XRD results of samples confirmed a single phase of SBT with orthorhombic crystal structure and a reduction in unit cell volume with the substitution of Holmium at B-site. The improvement in the structural and microstructural properties greatly enhanced the electric properties of SBHT. SBHT (x = 0.02) sample showed the improved ferroelectric properties (remnant polarization Pr = 1.63 μC/cm2 and Coercive field Ec = 0.51 kV/cm) making them suitable for ferroelectric applications. High Curie temperature (TC = 626 °C), elevated dielectric constant (εr = 236) and low loss (tanδ = 0.062) are obtained with the substitution of Ho (for x = 0.03) at B- site of SBT. These ceramics have high TC and improved thermal stability which makes these apt for the applications in high temperature sensors.
Electrical studies on Na and Sm substituted strontium bismuth titanate (SBTi) ceramics U. Ravikiran, P. Sarah, Elizabeth Zacharias Ferroelectrics, 2021 Single-phase Sodium (Na), Samarium (Sm) substituted Strontium Bismuth Titanate (SNSBTi I-V) ceramics were synthesized by solid-state double sintering approach via high energy planetary ball mill for 20 hours grinding. X-ray diffraction (XRD) study confirms the primary structure and orthorhombic distortion of crystal. Scanning electron microscopy (SEM) shows the grain orientation and densified plate-like grain structure of SNSBTi I-V. The complex impedance spectroscopy method was used to study the temperature and frequency dependent electric properties of the material using a high-frequency LCR meter. Z'' versus frequency plots have shown the peak shifting to higher frequencies with increasing concentration of Na, Sm. It is also found that the magnitude of the peaks decreases with increasing temperature. The grain and grain boundary relaxation mechanisms of SNSBTi I-V have been identified using Nyquist plots; the resistance, capacitance and relaxation times were obtained from Z-view software. It is seen that the grain and grain boundary resistances decreased with the increasing concentration of Na and Sm of SBTi ceramics.
Effect of neodymium and zirconium substitution on electrical properties of SrBi4Ti4O15 B. Mamatha, K. Ashok, A. R. James, P. Sarah Ferroelectrics, 2021 Neodymium and zirconium modified strontium bismuth titanate ceramics with content changing from 2.5 to 10 at% Nd and a 2.5 at% Zr of SrBi4Ti4O15 (SrNdxBi4-xZryTi4-yO15, (x = 0.00, 0.025, 0.05, 0.075, and 0.1, y = 0.00 and 0.025) have been prepared by solid state reaction method and analyzed by X-ray diffraction (XRD), dielectric response, ferroelectric hysteresis, electromechanical coupling coefficient, and piezoelectric charge coefficient. From hysteresis loop, the remnant polarization and coercive field were calculated and explained. Dielectric analysis explained the sample behavior. Piezoelectric charge and electromechanical coupling coefficients were found to be increased with the addition of Zr and Nd.
Modeling of dielectric data of mechanically milled strontium calcium bismuth titanate using modified Lorentz equations Gagan Anand, Morgan Putier, A. R. James, P. Sarah Ferroelectrics, 2021 Oxides of strontium, bismuth, calcium, and titanium were aggregated by high energy mechanical milling. XRD and SEM analyses revealed characteristic peaks for materials of a similar crystal structure. The temperature response of dielectric constant has been recorded at various frequencies. An increase of dielectric constant until the Curie temperature has a huge impact on the dielectric constant. A transformed version of the Lorentz equation is suggested to match experimental results and find the activation energy. To ensure the reliability of our formula, the value from the non-linear curve fitting is checked for each trial. The activation energy was found to be in the range of 80–90 μeV.
Modelling of Dielectric Studies on Rare-Earth Substituted Strontium Bismuth Titanate Using Modified Lorentz Equation Ravikiran Uppala, Elizabeth Zacharias, Gagan Anand, Pasala Sarah Integrated Ferroelectrics, 2021 Samarium, Sodium modified Strontium Bismuth Titanate ceramics were prepared using solid-state sintering approach. Calcined powders obtained after treatment at 800 °C for 120 min were pressed into1 cm diameter and 1 mm thick pellets using uniaxial hydraulic press. These pellets were sintered at 1160 °C for 120 min in a programmable furnace. XRD studies confirmed single-phase Orthorhombic structure and SEM micrographs identified the sheet-like grain formation with no preferred alignment. Dielectric data was matched with modified Lorentz equation to ensure the reliability of the obtained experimental results. The activation energies (Ea) of samples were found to be in the range 70–85 μeV.
