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The increasing popularity of wearable electronics has sparked interest in flexible energy harvesters as alternatives to conventional batteries. Flexible magnetoelectric (ME) composites, known for converting ambient magnetic field energy into useable power, are emerging as promising autonomous energy sources for integration into wearable devices. In this study, we prepared flexible (PVDF-AlN)–(NiO–CNF) based ME composites using two different methods: solution-casting and electrospinning techniques. The ME coupling was confirmed by measuring the ferroelectric and magnetic properties of the composite, and it was qualitatively characterized through the ME coupling coefficient. The electrospinning fibers-based ME composite exhibited an optimal value of 10.6 V/cm.Oe, significantly higher than the solution-casting films-based ME composite (1.3 V/cm.Oe) under a 1 kHz AC magnetic field (off-resonance condition). Subsequently, a flexible magneto-mechano-electric (MME) generator was designed using electrospun-derived material, harvesting a sinusoidal wave with a maximum output peak-to-peak voltage of 9.02 V. The generator displayed an optimal DC power density of 97 μW/m2 when exposed to a weak AC magnetic field of 6 Oe at a frequency of 50 Hz. Consequently, it holds great promise as an efficient autonomous power supply for medical sensing and various miniature electronic applications. [ABSTRACT FROM AUTHOR]

Pulsed power and power electronics systems used in electric vehicles (EVs) demand high-speed charging and discharging capabilities, as well as a long lifespan for energy storage. To meet these requirements, ferroelectric dielectric capacitors are essential. We prepared lead-free ferroelectric ceramics with varying compositions of (1 − x)Ba0.7Sr0.3TiO3–(x)BiMg0.5Ti0.5O3 (BST–BMT) (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1) using a solid-state-reaction method. To analyze the crystallinity and structural parameters, we examined the X-ray diffraction (XRD) patterns using the pseudo-Voigt function in the FullProf software. Additionally, Raman spectrum analysis confirmed the presence of ceramic structural distortion caused by microstrain and doping. Microstructure images of the ceramic samples showed an increase in grain size from 1 to 2.4 μm and an improved distribution of grain sizes with increasing doping levels. We investigated the dielectric properties of the BST–BMT ceramic capacitors across a wide range of frequencies and temperatures. Interestingly, as the BMT content increased, the previously saturated ferroelectric (FE) curve for x = 0.01 gradually shifted towards a narrower relaxor ferroelectric (RFE) curve for x = 0.1. The most favorable effective energy storage density was observed with a BMT doping concentration of x = 0.04, which coincided with exceptionally high-energy efficiency (η ~ 91%) under a field strength of 50 kV/cm and a relatively high dielectric normalized energy storage density of 3.71 µJV−1 cm−2 due to structural modifications that causes relaxor ferroelectric behavior. More interestingly, the energy storage performance of 0.96BST–0.04BMT displays a fatigue free characteristic enduring through numerous switching cycles. We also calculated the optical bandgap (Eg) values from UV–Vis spectra and compared them with the increase in BMT concentration. The Eg value for all ceramics was approximately 3.2 eV, similar to the pure BST ceramic sample. Additionally, the resistive switching behavior demonstrated by our bulk ceramic capacitors is not commonly observed in other bulk ceramics. [ABSTRACT FROM AUTHOR]

Magneto-mechano-electric (MME) generators efficiently harness ubiquitous stray magnetic fields and convert them into electricity, capturing significant attention for powering innumerable wireless sensors. In this study, lead-free 0-3 particulate magnetoelectric (ME) nano-composite ceramics, specifically x(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3)-(1-x)Ni 0.5 Zn 0.5 Fe 2 O 4 [x(BCT-BZT)–(1-x)NZFO], were synthesized using the sol-gel method. Subsequently, a flexible MME generator was designed, incorporating the optimized ME composite. Structural parameter calculations indicated higher tetragonal distortion of 0.4% in 0.4(BCT-BZT)-0.6NZFO, possibly due to uniform particulate distribution. The ME composites displayed uniform dual-phase microstructures, with 0.4(BCT-BZT)-0.6NZFO showing a higher NZFO concentration. The maximum values of the magnetodielectric (MD) and ME coupling coefficients have been determined to be -3.6% and 2.55 mV cm -1 Oe-1, respectively, for an x = 0.4 composite. The MME generator is designed using an optimized 0.4(BCT-BZT)-0.6NZFO ME composite with film thickness of 34 μm. This MME generator harvests a sinusoidal wave with a maximum output peak-to-peak voltage of 4.1 V when exposed to a weak AC magnetic field of 10 Oe at a frequency of 50 Hz. Additionally, the device demonstrates an exceptional optimal DC power density of 3.89 μW cm-3. The lead-free 0-3 particulate ME composite enables effective magnetic energy harnessing. As a result, it holds great promise as an efficient autonomous power supply for various Internet of Things based applications. [ABSTRACT FROM AUTHOR]

Magneto-mechano-electric (MME) generators efficiently harness ubiquitous stray magnetic fields and convert them into electricity, capturing significant attention for powering innumerable wireless sensors. In this study, lead-free 0-3 particulate magnetoelectric (ME) nano-composite ceramics, specifically x(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3)-(1-x)Ni 0.5 Zn 0.5 Fe 2 O 4 [x(BCT-BZT)–(1-x)NZFO], were synthesized using the sol-gel method. Subsequently, a flexible MME generator was designed, incorporating the optimized ME composite. Structural parameter calculations indicated higher tetragonal distortion of 0.4% in 0.4(BCT-BZT)-0.6NZFO, possibly due to uniform particulate distribution. The ME composites displayed uniform dual-phase microstructures, with 0.4(BCT-BZT)-0.6NZFO showing a higher NZFO concentration. The maximum values of the magnetodielectric (MD) and ME coupling coefficients have been determined to be -3.6% and 2.55 mV cm -1 Oe-1, respectively, for an x = 0.4 composite. The MME generator is designed using an optimized 0.4(BCT-BZT)-0.6NZFO ME composite with film thickness of 34 μm. This MME generator harvests a sinusoidal wave with a maximum output peak-to-peak voltage of 4.1 V when exposed to a weak AC magnetic field of 10 Oe at a frequency of 50 Hz. Additionally, the device demonstrates an exceptional optimal DC power density of 3.89 μW cm-3. The lead-free 0-3 particulate ME composite enables effective magnetic energy harnessing. As a result, it holds great promise as an efficient autonomous power supply for various Internet of Things based applications. [ABSTRACT FROM AUTHOR]

Mechanical energy harvesting and energy storage through lead-free piezoelectric materials is an inevitable source of eco-friendly sustainable powering of electronic devices. Herein, we have synthesized amphoteric rare-earth element praseodymium (Pr) modified Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) ceramics, with a cost-effective solid-state-reaction based two-step sintering method for the controlled grain growth. Their crystalline structures and surface morphology were investigated by using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The dielectric and ferroelectric properties of the ceramic capacitors were investigated and correlated with structural parameters. In the vicinity of the monotonic phase transition region, with the coexistence of orthorhombic and tetragonal symmetry, the Pr ion addition in BCZT improves the tetragonal phase, which widens its energy harvesting and storage arena. The appreciable energy harvesting ability was found for an optimized energy harvester with a composition of 0.04 wt% Pr added BCZT ceramic, with an open-circuit voltage of about 5.1 V (corresponding power density of 1.213 mW/cm3) from a simple finger tapping and bring about output voltage stability with a maximum output voltage of about 9 V over 10,000 cycles when periodic force is applied by a machine tapping. Furthermore, this optimized Pr added BCZT ceramic capacitor is capable of storing a substantial recoverable energy density of 81.9 mJ/cm3with a considerable energy storage efficiency of 76.4%. These upshots offer a head start in implementing these ceramic capacitors for effective energy harvesting and energy storage applications for powering futuristic miniature electronics. ● The amphoteric praseodymium (Pr) modified BCZT ceramics were synthesized through the two-step sintering (TSS) method. ● The dielectric, ferroelectric properties and energy storage behavior got enriched for the Pr modified BCZT ceramics. ● The optimum ceramic-based mechanical energy harvester offers voltage stability of ~ 9 V for 10,000 cycles. ● The recoverable energy density of 81.9 mJ/cm3 and energy efficiency of 76.4% attained. [ABSTRACT FROM AUTHOR]

• Vacuum and air sintered Bi-doped YIG have been prepared along with pure YIG using the sol–gel auto-combustion method. • The dielectric properties have enriched, and tangent loss has decreased for vacuum sintered Bi-doped YIG compared to YIG and air sintered Bi-doped YIG ceramics. • It also shows the better dielectric response with applied magnetic field so that it can be used for field sensing applications along with passive microwave devices. • We have observed large magneto-electric effect at the room temperature for all the ceramic samples and YBIG-V ceramic is maximum among them. • We have correlated the enhanced dielectric characteristics to the magnetic properties obtained through VSM measurements and attribute to the reduction in deficit oxygen states or Fe2+ concentration due to the vacuum sintering process which has also been confirmed through XPS studies. Yttrium iron garnet (YIG; Y 3 Fe 5 O 12) is an important material in the field of electronics because of its unique magnetic properties. This makes it ideal for use in devices such as microwave filters, amplifiers, sensors, and even magnetic storage devices. It is also used in spintronics, which is the study of the spin of electrons and how it can be manipulated for storage and computation. Additionally, it is highly stable and has low losses when exposed to electromagnetic fields, making it useful in applications such as controlling electric properties with magnetic fields or vice-versa, and magnetic resonance imaging (MRI). Herein, we have prepared YIG and Bi-doped YIG (Bi: YIG: Y 2 Bi 1 Fe 5 O 12) nanoparticles (NPs) using the sol–gel auto-combustion method. The obtained garnet powders were sintered at 950 °C both in an air and vacuum environment. We have explored the structural, electrical, optical, magnetic, and magneto-electric (ME) properties of Bi-doped YIG sintered in a vacuum (YBIG-V) and compared it with YIG and Bi-doped YIG sintered in the air (YBIG-A). We found the enhancement in dielectric response, magnetic properties, and the reduction in leakage current for the YBIG-V ceramics than for YBIG-A, YIG ceramics. We have studied the magneto-electric (ME) coupling at room temperature and found that YBIG-V ceramics show the better coupling strength with a maximum coupling coefficient, α ME of 354.3 mV/cm-Oe. The dielectric response of these samples significantly varies with the applied magnetic field, which will be positive in Bi-doped YIG ceramics and negative in pure YIG ceramics. Compared to YBIG-A, YBIG-V samples have better variation in dielectric response with the magnetic field, due to which they may be utilized for magnetic field sensing applications. We also observed that the resonance frequency varies with the applied magnetic field, which may be another parameter for field sensing applications. We attribute the enhancement of these properties in YBIG-V sample to the reduction in the average oxygen valency which is 1.63 for YBIG-A and 1.58 for YBIG-V. These values have been determined with the help of X-ray photoelectron emission spectroscopy data. [ABSTRACT FROM AUTHOR]