http://ore.immt.res.in/handle/2018/1 Sat, 22 Aug 2026 23:06:03 GMT 2026-08-22T23:06:03Z http://ore.immt.res.in/handle/2018/4012 Nanoscale polarization switching and magneto-piezoelectric coupling in MgFe2O4-PVDF-HFP nanocomposites for low-field magnetic energy harvesting and self-powered IoT microsystems Priyadarshini, B. S.; Kalita, D.; Noble, N.; Bais, G.; Topwal, D.; Manju, U. Magneto-piezoelectric technology has emerged as a promising multifunctional platform for hybrid and self-powered sensing systems, wearable electronics, and low-power internet-of-things (IoT) applications by harvesting both mechanical vibrations and stray magnetic fields. In this study, we demonstrate a compositionally optimized magneto-piezoelectric composite where the calculated incorporation of MgFe2O4 nanofillers into electroactive PVDF-HFP matrix enables efficient synchronization between magnetic stimulus, mechanical deformation and piezoelectric charge generation. The optimal composition with superior beta-phase nucleation, MF-3, shows the highest maximum polarization of 7.3 nC cm-2 with a recoverable energy density of 0.67 & micro;J cm-3 at a low electric field of 220 V m-1. Nanoscale Switching Spectroscopy-Piezoelectric Force Microscopy measurements reveal a displacement of 1.8 nm and a near-complete phase reversal of 170 degrees, confirming a reversible polarization switching at the domain level. The prototype magneto-piezoelectric nanogenerator fabricated with MF-3 film generates a high peak-to-peak voltage of 97.5 V under dynamic mechanical excitation via human finger tapping motion, higher than widely studied spinel fillers. Most notably, the MF-3 composite exhibits a distinct magneto-piezoelectric response, generating a voltage of similar to 40 mV when exposed to a low magnetic field of 320 & micro;T, originating from the coupling of the magnetic and piezoelectric phases that efficiently transfers the magnetic strain as a stimulus to the electroactive composite. The device successfully powers multiple light-emitting diodes and charges a capacitor of 1 & micro;F to 4.5 V under 2.5 s under tactile activation through repetitive finger tapping. This study not only unveils a highly effective design for harvesting energy from stray magnetic fields but also highlights the transformative potential of magneto-piezoelectric technology as an essential multifunctional strategy in next-generation technological advancements. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/4012 2026-01-01T00:00:00Z http://ore.immt.res.in/handle/2018/4011 Mechanical and tribological response of red brick dust filled hemp-epoxy composites using response surface methodology and machine learning approach Fuloria, D.; Pati, P. R.; Nayak, S. K.; Mahapatra, S. K.; Agrawal, A.; Purohit, A.; Gupta, G. The current study focuses on the wear and mechanical properties of epoxy-based hybrid composites that contain hemp fiber and red brick dust (RBD). The hand lay-up method is used for making composites using hemp fiber (40 wt%) reinforced epoxy with varied RBD loading up to 15 wt%. The prepared samples are assessed by investigating their physical, mechanical and tribological behavior. The results revealed that the density increased from 1.257 to 1.338 g/cm & sup3; with increasing RBD content, while tensile and flexural strengths decreased by approximately 13.3 and 7.4%, respectively, at 15 wt% filler loading. In contrast, impact strength and hardness improved significantly, showing enhancements of 144 and 152%, respectively, compared to neat epoxy. The sliding wear tests are also carried out in accordance with the L30 model of response surface methodology (RSM). According to reports, the two most important factors affecting the composites' wear rate are RBD content and sliding velocity. The developed RSM models showed good agreement with experimental results, with prediction errors within +/- 5%. Additionally, an efficient model for predicting the wear characteristics of the RBD-filled hemp-epoxy composites is developed using three machine learning (ML) models: decision tree (DT), random forest (RF), and gradient boosting machine (GBM). Among them, the GBM model demonstrated superior performance, achieving the highest accuracy with R & sup2; values of 0.9542 for specific wear rate and 0.9879 for coefficient of friction, along with the lowest prediction errors. Moreover, the investigation revealed that filler content and normal load are the most important variables affecting the estimation of specific wear rate and COF, respectively. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/4011 2026-01-01T00:00:00Z http://ore.immt.res.in/handle/2018/4009 Study on liquid phase flash sintering of 3YSZ assisted by ZnO-Cu2O eutectic Singh, S. K.; Raj, R.; Nayak, Bibekananda; Mundra, R.; Jha, S. K.; Yadav, D.; Chakrabarti, T. This work examines liquid phase flash sintering (LPFS) of 3 mol% yttria-stabilized zirconia (3YSZ) co-doped with 1-10 wt% ZnO-Cu2O eutectic (CZ). During flash sintering, Joule heating rapidly elevates temperature beyond the CZ eutectic point (similar to 1100 degrees C), generating a liquid phase that drives accelerated densification. XRD analysis demonstrated substantial solubility of Cu+ and Zn2+ ions into the zirconia lattice, which lowered the theoretical density while achieving optimal densification (>96% relative density) at 2.5 wt% CZ. XPS revealed elevated oxygen vacancy concentrations in flash sintered samples relative to those conventionally sintered. EIS indicated that the 2.5 wt% CZ variant exhibited superior ionic conductivity and minimal activation energy. Finite element analysis confirmed average temperatures during flash sintering higher than the eutectic point. Overall, these findings validate moderate CZ co-doping paired with flash sintering as a strategy to engineer defect chemistry and microstructure, enabling breakthroughs in SOFC electrolytes and low-temperature ceramic processing. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/4009 2026-01-01T00:00:00Z http://ore.immt.res.in/handle/2018/4007 Towards Battery Like Energy Density of MnO2 Electrodes in Water-in-Salt Electrolyte Environments Das, A.; Sahu, S.; Dash, M.; Mohapatra, M. Enhancing the energy density of supercapacitors (SCs) is essential for advancing their capabilities, broadening their range of applications, and making them more competitive with other energy storage technologies like batteries. Although aqueous SCs are emerging as a desirable technology, their energy density is severely restricted by the low thermodynamic stability window of aqueous electrolytes. Achieving a high-energy supercapacitor that leverages the benefits of an aqueous electrolyte is both highly desirable and challenging. In this study, we address this challenge by utilizing a water-in-salt 17 m NaClO4 (WiS) electrolyte that allows an operational window of 2.87 V, coupled with engineered potassium-incorporated manganese dioxide (K-MnO2) electrode. Our research demonstrates that the insertion of potassium ions (K+) into manganese dioxide (MnO2) significantly enhances its pseudocapacitive behavior via the Mn3+/Mn4+ redox mechanism. This enhancement, facilitated by the wide potential range provided by the electrolyte, results in a high areal capacitance of 1051 mF/cm2 (294.3 F/g). Furthermore, the asymmetric supercapacitor, featuring an activated carbon negative electrode and K-MnO2 positive electrode, operates at 2.3 V, achieving an energy density of 59.5 Wh/kg. This study underscores the critical role of well-defined electrochemical interfaces in enhancing the energy density of SCs. It also offers a powerful approach to utilizing WiS electrolytes, enabling wide-window operation of electrodes in aqueous SCs to achieve battery-like energy densities. Thu, 01 Jan 2026 00:00:00 GMT http://ore.immt.res.in/handle/2018/4007 2026-01-01T00:00:00Z