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Relaxor ferroelectrics are technologically important materials for applications in, for example, high-temperature capacitors, transducers and nano-positioning systems. These materials have often been reported to exhibit surface or skin layers with distinct physical properties to the bulk. The control of formation and functionality of these skin layers has remained elusive and is becoming increasingly critical due to device miniaturization, where the surface contribution to overall material properties becomes significant. We recently demonstrated that the distinct structural distortion of the skin layer is intimately related to the internal chemical pressure applied by oxygen vacancies and the plane stress conditions at the surface. (S. Kong, N. Kumar, S. Checchia, C. Cazorla and J. Daniels, Adv. Funct. Mater., 2019, 29, 1900344) Here, we demonstrate a unique capability to control the formation and properties of the skin layer through the control of defect concentration. Most interestingly, the skin layer is polar and both electrically and optically active, making it functional and a new candidate for low operating voltage and/or optoelectronic devices. The surface domains in the skin could be altered by applying a small voltage bias (1000 times lower than bulk) or light illumination. A reversible optical change in surface domains provides a new non-contact external control to tune the material polarisation.

Chen et al. (2020) used schematics to claim that a temperature-dependent change in polarisation could not lead to a change in polar entropy of single and polycrystalline materials and hence should not be used for estimating electrocaloric effect (ECE) performance using Maxwell relations. Through this article, we explain how this reasoning does not fit well to our ECE estimates for PbZr0.53Ti0.47O3 (PZT) and CoFe2O4 (CFO) heterostructures in Vats et al. (2016). In addition, a detailed explanation of the calculation of ECE performance in our heterostructures is presented since Chen et al. (2020) reported difficulty in understanding how ECE calculations in particular temperature ranges, that were away from the highest ECE temperature, were related to the polarisation versus temperature data.

This study reports the magnetocaloric effect (MCE) and piezoresponse of integrated ferroelectric-ferromagnetic heterostructures of PbZr 0.52Ti 0.48O 3 (PZT) (5 nm)/Bi-Sr-Ca-Cu 2-O X (BSCCO) (5 nm)/La 0.67Sr 0.33MnO 3 (LSMO) (40 nm)/MgO (0 0 1). Magnetic and pizoresponse behavior of the heterostructures are found to be governed by magneto-electric coupling and induced lattice strains. In addition, a maximum MCE is studied using Maxwell equations from both Field Cooled (FC) and Zero Field Cooled (ZFC) magnetization data. Maximum MCE entropy change (|ΔS|) of 42.6 mJkg −1K −1 (at 258 K) and 41.7 mJkg −1K −1 (at 269 K) are found corresponding to FC and ZFC data, respectively. The variation in maximum entropy change and corresponding temperatures for FC and ZFC data revealed that the application of a magnetic field can significantly contribute towards tuning of the MCE. Interestingly, these multilayered structures are found to sustain MCE over a broad temperature range, which makes them attractive for improved solid-state energy conversion devices.

Multiferroic composites of Zn-Cr substituted cobalt ferrite (Co0.75Zn0.25Cr0.2Fe1.8O4) (CZCFO) nanoparticles and lead-free piezoelectric sodium bismuth titanate Na0.5Bi0.5TiO3 (NBT) having composition (1 − x) Na0.5Bi0.5TiO3 + (x)Co0.75Zn0.25Cr0.2Fe1.8O4 (x = 0.0, 0.25, 0.5, 0.75, 1.0) were investigated in this study. Ferromagnetic-CZCFO and ferroelectric-NBT phases were synthesized via sol-gel auto combustion route and solid-state reaction methods respectively. The structural properties of composite materials were studied using X-ray diffraction (XRD) technique. Intense and sharp peaks observed in XRD patterns confirm that both the phases are well crystalline in nature. Two separate phases of CZCFO and NBT are present in composite material without any impurity or chemical reaction among them. The morphology of prepared samples was studied via scanning electron microscopy confirming that composite materials are well-densified and homogenous grain size distribution. The magnetic hysteresis loops of multiferroic composite were investigated by using vibrating sample magnetometer at room temperature. The lead free multiferroic composite exhibiting a large converse magneto-electric (ME) effect at room temperature. The maximum value of ME coefficient (αME = 7.92 kV/cm) is obtained at x = 0.50. Furthermore, electrical properties of nanocomposite material were studied by P-E hysteresis loop and dielectric measurements at room temperature.

The piezo-photovoltaic effect has been recently proposed as an analogy of the flexo-photovoltaic effect in noncentrosymmetric ferroelectrics that are also piezoelectric in nature. It has been demonstrated to boost the photovoltaic performance of ferroelectrics under applied uniaxial mechanical loads. The impact of the piezo-photovoltaic effect on ferroelectric domains, however, has not yet been studied. In this context, a nanoscale insight into mechanical as well as optomechanical control of domains in a novel bandgap-engineered ferroelectric, namely—KNBNNO ((K0.5Na0.5)NbO3–2 mol% Ba(Ni0.5Nb0.5)O3−δ), is provided. It is found that the applied mechanical force of 1 μN (pressure: 0.25 GPa) using a scanning probe tip evinces a 67% amplification in piezoresponse in the material, and on removing mechanical load, the material retains 33% higher piezoresponse than the pristine state. Mechanically induced property changes in the material are found to be strongly influenced by light illumination. Applied mechanical stress due to an atomic force microscopy (AFM) tip is highly nonuniform and can induce additional polarization via the flexoelectric effect which further enhances the photovoltaic charge screening.

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Topologically nontrivial spin textures such as vortices, skyrmions, and monopoles are promising candidates as information carriers for future quantum information science. Their controlled manipulation including creation and annihilation remains an important challenge toward practical applications and further exploration of their emergent phenomena. Here, we report controlled evolution of the helical and skyrmion phases in thin films of multiferroic Te-doped Cu2OSeO3 as a function of material thickness, dopant, temperature, and magnetic field using in situ Lorentz phase microscopy. We report two previously unknown phenomena in chiral spin textures in multiferroic Cu2OSeO3: anisotropic scaling and channeling with a fixed-Q state. The skyrmion channeling effectively suppresses the recently reported second skyrmion phase formation at low temperature. Our study provides a viable way toward controlled manipulation of skyrmion lattices, envisaging chirality-controlled skyrmion flow circuits and enabling precise measurement of emergent electromagnetic induction and topological Hall effects in skyrmion lattices.

Optoelectric control of domains is likely to pave the foundation for optoferroelectric devices. This work reports the combined effect of light and low-voltage electric bias for optoelectric control of ferroelectric domains in a semiconducting ceramic material—KNBNNO ((K0.5Na0.5)NbO3 doped with 2 mol % Ba(Ni0.5Nb0.5)O3−δ). The effect is utilized to achieve two orders of magnitude amplification in electrical response, asymmetric AC modulation, and domain velocities of 30 000 nm s–1 with ultralarge domain switching areas of over 30 μm in fractions of a second. The charge injection due to light illumination on this material causes the tuning of material conductivity and acts as a virtual electrode. Based on this mechanism, a proof of concept for a monolithic ferroelectric light-effect transistor with a source and drain as electrical contacts with light acting as a virtual gate is demonstrated. This is likely to offer a potential solution to the scaling limit of conventional three-terminal transistors. The same device is also demonstrated to work as a photodiode, a half-wave rectifier, and an electrical output modulator.

The present work demonstrates ferroelectric to antiferroelectric transition aided electric field control of positive and negative electrocaloric effects (ECE). In this context, epitaxial PbZrO3 (PZO) thin films were grown on (111) Nb:SrTiO3 single crystal substrates by the sol–gel method, and the epitaxial growth was confirmed by atomic resolution scanning transmission electron microscopy (STEM) high angle annular dark field (HAADF) images. The structural and elemental analysis revealed a gradual increase of natural lead volatilization from the middle to the top in PZO thin films. The electrocaloric effect (ECE) was calculated using Maxwell equations corresponding to 10 kHz and 100 Hz P–E data and was found to be −10.5 K (negative ECE) at 375 K and 30 K (positive ECE) at 300 K. Intriguingly, both negative and positive ECE were found in the same phase transition sequence, that is, from an antiferroelectric phase to a ferroelectric phase. The frequency dependence of ECE is found to be dependent on the polarization switching dynamics and kinetics. These results are not only scientifically important for providing an easy way to combine the negative and positive ECE together to further enhance the cooling efficiency but are also technically important for future ECE devices.

Energy crisis and increasing demand for green energy to acute pollution has forced the engineers, architects and scientists to adapt green materials for structural applications. In this context, conventional building materials are extensively investigated using life cycle estimations, thermodynamic models, CO2 emissions, and energy demands and many other criteria. Selection of smart materials for thermal energy efficient architecture on the bases of various thermo-physical properties (density (ρ), thermal conductivity (K) and specific heat capacity (Cp)) in relation to the engineering requirements (energy stored (QS), energy density (Q′), rate of heat transfer (q), utilization factor (η) and mechanical load) is a crucial as well as a tedious task. In this context, we have employed quality function deployment (QFD) in combination with VlseKriterijumska Optimisacija I Kompromisno Resenje (VIKOR) technique to determine the ranks and rank indices (degree of closeness) of important materials. The weights of thermo-physical properties of materials for hot (ρ: 17.72%; Cp: 45.14%; K: 37.14%) and cold weather (ρ: 29.32%; Cp: 65.42%; K: 5.26%) applications are depicted using QFD. Our results enlighten that low conductivity materials should be preferred for hot areas applications while for cold areas the scenario is reversed. Furthermore, wood and asphalt sheet are found to be the best materials for hot and cold areas, respectively.

Present study exhibits an experimental examination of mass transfer coefficient and evaporative effectiveness of a falling film evaporator. Further, a statistical replica is extended in order to have optimal controlling parameters viz. non-dimensional enthalpy potential, film Reynolds number of cooling water, Reynolds number of air and relative humidity of up-streaming air. The models not only give an optimal solution but also help in establishing a correlation among controlling parameters. In this context, response surface methodology is employed by aid of design of experiment approach. Later, the response surface curves are studied using ANOVA. Finally, the relations established are confirmed experimentally to validate the models. The relations thus established are beneficent in furtherance of designing evaporators. Additionally, the present study is among the first attempts to reveal the effect of humidity on the performance of falling film evaporator.

Present study is among the first attempts to prioritize the prominent Indian states for better utilization of available solar resources. In this context, potentiality indices are performed on the basis of six prime factors that influence the effective utilization of solar energy and ranking is done accordingly. Firstly, in order to determine the weightage and hierarchy of the evaluation parameters modified digital logic (MDL) approach is employed. Availability of solar radiation is found to be the most influential parameter. Thereafter, fuzzy-analytical hierarchy process (AHP) is used for determination of the potentiality index and the corresponding ranking of different states. The ranks thus obtained are compared to current installed capacity ranks. It is found that a few states despite of high potential for the exploitation of solar energy are not getting proper attention by their respective governments. In order to promote the solar energy exploitation in such states it becomes vital to identify the vital parameters that may lead to the improvement in the current ranking. In this direction, sensitivity analysis is performed to determine the percentage change in distinct parameters which is required for the upgradation in the ranking. Such studies are capable to make a paradigm shift in technology utilization and formulation of energy policies as the proposed approach provides a concrete layout for re-evaluation of current policies as well as formulation of newer ones.

This article reports the peculiarity in the thermo-electrical energy conversion (by Olsen cycle) capability of Bi0.5Na0.5TiO3-xBaTiO3 (BNT-BT) system caused by the coupled effect of structural transformations and phase transitions in vicinity of the morphotropic phase boundary (MPB). The calculated maximum energy density estimated for nearly identical ambient conditions for MPB (x = 0.06) lies in the range of 40–110 J/L (40–110 kJ/m3) while moving away from the MPB the same elevates dramatically on both the ends. The utmost energy density found in system is 1000 J/L (1000 kJ/m3) for BNT-0.3BT (temperature range: 42.6–108.7°C; applied electric field: 0–6.5 MV/m). This energy density is significantly higher than the reported thermo-electrical energy generation (680 kJ/m3) using negative electrocaloric effect in BNT-xBT systems. It is found that ferroelectric to antiferroelectric transition as well as transformation suppresses harvested energy density at MPB. Contemporary, rhombohedral to tetrahedral...

This article reviews the basics of ferroelectric energy harvesting cycles based on thermal fluctuation and mechanical confinement. In this context, five cycles (Olsen cycle, Clamped Olsen cycle, Electro-Mechanical cycle, Thermally Biased Electro-Mechanical cycle and New Power cycle) are studied for two different compositions (0.94Bi1/2Na1/2TiO3–0.06BaTiO3: BNT–6BT; 0.91(Bi1/2Na1/2)TiO3–0.07BaTiO3–0.02K0.5Na0.5NbO3: BNT-BT-KNN;) which represents two distinct classes (based on domain wall rotation/motion) of ferroelectric materials. These can be classified as the composition with dominating impact of mechanical forces while the other is with ascendant thermal effects over the domain wall behavior.

An insight into the analogies, state-of-the-art technologies, concepts, and prospects under the umbrella of perovskite materials (both inorganic–organic hybrid halide perovskites and ferroelectric perovskites) for future multifunctional energy conversion and storage devices is provided. Often, these are considered entirely different branches of research; however, considering them simultaneously and holistically can provide several new opportunities. Recent advancements have highlighted the potential of hybrid perovskites for high-efficiency solar cells. The intrinsic polar properties of these materials, including the potential for ferroelectricity, provide additional possibilities for simultaneously exploiting several energy conversion mechanisms such as the piezoelectric, pyroelectric, and thermoelectric effect and electrical energy storage. The presence of these phenomena can support the performance of perovskite solar cells. The energy conversion using these effects (piezo-, pyro-, and thermoelectric effect) can also be enhanced by a change in the light intensity. Thus, there lies a range of possibilities for tuning the structural, electronic, optical, and magnetic properties of perovskites to simultaneously harvest energy using more than one mechanism to realize an improved efficiency. This requires a basic understanding of concepts, mechanisms, corresponding material properties, and the underlying physics involved with these effects.

Nanocrystalline Ce-substituted yttrium iron garnet (YIG) powders of different compositions, Y3−xCexFe5O12 (0 ≤ x ≤ 2.0), were synthesized by a combination of sol–gel auto-combustion and solid-state synthesis techniques. The as-obtained powder samples were sintered at 1150 °C for 10 h. The garnet structure formation is confirmed by the X-ray diffraction pattern, which shows that the calculated lattice parameter increased for x = 1.0 and shows a decreasing trend for x ≥ 1.0 with the addition of cerium ions. The lattice parameter increased from 12.38 A to 12.41 A for x ≤ 1.0 whereas it decreased from 12.412 A to 12.405 A with the cerium composition for x > 1.0. The average particle size determined by high resolution transmission electron microscopy is in the range of 50 to 90 nm and found to increase with the substitution of cerium ions in YIG. The room temperature magnetic parameters such as saturation magnetization, coercivity and remanence magnetization are greatly affected by the substitution of cerium ions. The values of saturation magnetization decrease from 25.5 to 15 emu g−1 whereas coercivity increases from 1 to 28 Oe with the substitution of cerium ions. The pure YIG sample shows polycrystalline nature that changed towards a single-crystal structure leading to a preferred-(100) orientation with the Ce substitution. The change from a ring to a spotty pattern observed in SAED confirmed the crystalline phase transformation and is well supported by HRTEM and magnetic measurements. The behavior of magnetic and electrical properties is well supported by the poly- and single-crystalline nature of YIG and Ce-YIG, respectively. The crystal structure transformation in YIG brought about by Ce substitution could unveil enormous opportunities in the preparation of single-crystal materials from their polycrystalline counterparts.

Concrete is the most used material for the construction in the modern time of infrastructures. Concrete is strong in compression but it is weak in tension and shear. To minimise those problems, fibres were introduced in concrete to enhance its tensile strength and shear strength. In my present investigation, the mechanical properties of fibres reinforced concrete are studied by using steel fibre, glass fibre and polyamide fibre with a different weight fraction of fibres with respect to cement. The mix design of M25 concrete with W/C ratio of 0.42 is prepared and total thirteen mixes included one control mix was prepared and tested in the laboratory. The total quantity of fibres mixed in the concrete are in order of 0%, 0.75%, 1.5%, and 2.25% by weight of cement and one mix contains 0.33% of glass fibre, 0.33% of steel fibre and 0.33% of polyamide. The study shows that the mixed fibres provide better properties in controlling cracks and high strengths than single fibre and concrete without fibre. On increasing the percentage of fibres beyond 1.5%, the strength of the concrete matrix decrease due to mat form of fibres or non-uniform distribution of fibres and also decrease due to non-cohesiveness of the concrete particle to each other.

Photo‐ferroelectric single crystals and highly oriented thin‐films have been extensively researched recently, with increasing photovoltaic energy conversion efficiency (from 0.5% up to 8.1%) achieved. Rare attention has been paid to polycrystalline ceramics, potentially due to their negligible efficiency. However, ceramics offer simple and cost‐effective fabrication routes and stable performance compared to single crystals and thin‐films. Therefore, a significantly increased efficiency of photo‐ferroelectric ceramics contributes toward widened application areas for photo‐ferroelectrics, e.g., multisource energy harvesting. Here, all‐optical domain control under illumination, visible‐range light‐tunable photodiode/transistor phenomena and optoelectrically tunable photovoltaic properties are demonstrated, using a recently discovered photo‐ferroelectric ceramic (K0.49Na0.49Ba0.02)(Nb0.99Ni0.01)O2.995. For this monolithic material, tuning of the electric conductivity independent of the ferroelectricity is achieved, which previously could only be achieved in organic phase‐separate blends. Guided by these discoveries, a boost of five orders of magnitude in the photovoltaic output power and energy conversion efficiency is achieved via optical and electrical control of ferroelectric domains in an energy‐harvesting circuit. These results provide a potentially supplementary approach and knowledge for other photo‐ferroelectrics to further boost their efficiency for energy‐efficient circuitry designs and enable the development of a wide range of optoelectronic devices.

This work presents a novel user oriented approach that can relate materials science with technological applications in a more transparent, systematic and efficient manner. We have made an attempt to figure out the optimal (corresponding to best combination of material properties) sintering temperature of K0.5Na0.5NbO3 (KNN) for transducer and electrical energy storage applications. The weights and priority of vital physical properties for applications understudy are calculated using the quality function deployment (QFD) method. Losses (tanδ), charge storage properties (ϵr, Pr and EC) and elastic compliance (sE12 and sE11) are found to have negative priority for transducer application while in the other case d31, tanδ, sE12 and sE11 are spotted to have negative priority. Priority order for transducer and energy storage application is d31>kp>QM>Tc>tanδ>ϵr>Pr=EC=sE12=sE11>ρ and ϵr>d31=tanδ>sE12=sE11>Tc>Pr>EC>kp>ρ>QM, respectively. Finally, 1080°C (transducer) and 1120°C (capacitor) are the found to be the mo...

Present study unfurls the colossal energy harvesting potential of lead-free 0.88Bi0.5Na0.5TiO3-.02SrTiO3-0.1Bi0.5Li0.5TiO3 (BNT-ST-BLT) bulk ceramic using Olsen cycle. This material has been reported for its excellent ferroelectric properties in various aspects. The maximum harness-able energy density for this composition is found to be 2130 J/L in the temperature spectrum of 20–140°C and applied electric field of 0.1-6.0 MV/m. We found that the energy density of this material is 2.6 times higher than the maximum energy density documented for any lead-based ferroelectric ceramics reported to date. Prior to the present study, 8/65/35 PLZT (thick films) was reported for the highest energy density of 888 J/L (temperature range: 25–160°C; applied electric field: 0.2-7.5 MV/m).

Present study introduces a novel energy conversion cycle for giant electro-mechanical energy conversion using ferroelectric materials. The proposed cycle is used to perform indirect measurements for harnessable energy densities of two well-known configurations ((0.5PbZrO3-0.5Pb(Ni1/3Nb2/3)O3: (PZ-PNN) and 0.9Pb(Zr1/2Ti1/2)O3-0.1Pb(Zn1/3Nb2/3)O3: (0.9PZT-0.1PZN)). PZ-PNN is depicted to illustrate an energy density of 70 kJ/m3 under the conditions of 0–106 MPa applied stress and 1–15 kV/cm electric field. On the other hand, a maximum energy density of 50 kJ/m3 is obtained for 0.9PZT-0.1PZN under ambient conditions of 0–173 MPa compressive stress and 1 to 18 kV/cm electric field.

Present study deals with the adoption of newer technologies for developing nations. Most of the developing countries due to lack of resources perform techno-socio-economic analyses on the already existing models of the developed ones. Such adopted technologies may not perform effectively because of unlike socio-economic factors. Hence, it becomes important to select new technologies based on appropriate and suitable criteria with respect to a particular country. In this paper, we have demonstrated selection of optimal electronic toll collection (ETC) system for India. In this context, we have considered thirteen crucial parameters for selection of appropriate ETC system. Cost is found to be the pivotal selection criterion in India. Further, fuzzy logic based MADM (multiple attribute decision making) approach is employed for selection of optimal ETC system for India. RFID-based (radio frequency identification) ETC is found to be the most suitable alternative among all considered ETC technologies. Our results are in strong agreement with the report of apex committee, appointed by “Government of India (Ministry of Road Transport & Highways)” for implementation of ETC in India.

Phase change materials (PCM) are extensively investigated for latent heat thermal energy storage systems (LHTESS). Lack of understanding between materials properties and engineering requirements is the reported roadblock in the development efficient PCM based LHTESS. This study illustrates a methodology for selection of optimal PCM and simultaneously tries to bridge the gaps between materials science of PCM in contrast to the engineering requirements of LHTESS. Engineering requirements for such systems includes sensible heat (QSensible), latent heat (QLatent), heat of conduction (QConduction) and convection (QConvection), thermal efficiency, effectiveness and weight. These requirements depend on various thermo-physical properties such as latent heat of fusion (� ), density (� ), thermal conductivity (k), specific heat capacity (Cp). Therefore, we have employed quality function deployment (QFD) and analytic hierarchy process (AHP) in combination with classical multiple attribute decision making (MADM). Though both the methods provide quantitative weightage to the materials properties on the basis of verbal reasoning, QFD is a transparent approach and has additional benefit of addressing the aforementioned objectives in a more effective manner. Consequently, the final ranks and rank indices (for degree of closeness) of important PCM are determined using VlseKriterijumska Optimisacija I Kompromisno Resenje (VIKOR) technique. Stearic acid (QFD-VIKOR) and n-Octadecane (AHP-VIKOR) are found to be the top rated PCM for LHTESS.

This article demonstrates the energy harvesting capabilities of bulk lead-free ferroelectric materials using Olsen cycle. Lead-free compositions K[(Nb0.90Ta0.10)0.99Mn0.01]O3 (KNTM) and 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-50BCT) have been explored for their energy harvesting capabilities. Further, we studied the variation in energy density over wide range of applied temperature and electric field. The maximum harness-able energy density for KNTM and BZT-50BCT compositions are found to be 629 J/L (629 kJ/m3) and 87 J/L (87 kJ/m3), respectively. This estimated energy density, obtained for the bulk samples, is comparable with the highest energy density reported to-date (888 J/L for lanthanum-doped lead zirconate titanate (8/65/35 PLZT) thick films).

Lead-free piezoelectric ceramics are extensively investigated for the alternatives of lead-based piezoceramics. (K,Na)NbO3 (KNN), (Bi0.5Na0.5)TiO3 (BNT), and (Bi0.5K0.5)TiO3 (BKT)-based ceramics are reported as promising piezoelectric material families. Several researchers have reported solid solution of these ceramics using various chemical and physical routes. In this study, we have rank these materials using multiple attribute decision making techniques. KNN-LT-LS and 0.7BNT-0.2BKT-0.1(Bi0.5Li0.5)TiO3 are found to be top rank in all the materials of respective families under study. We have also reported Pareto-optimal (nondominated) lead-free piezoelectric ceramics for d33 and Tc parameters.

The selection of an optimal ferroelectric material according to the user requirements is a crucial as well as onerous task; examples of such requirements include high efficiency, sensitivity, wide operating temperature, and frequency range, compact size, low cost and low loss, etc. In this study, quality function deployment (QFD) in combination with multiple attribute decision-making (MADM) is employed for material selection. Pb(1-x)Lax)(ZryTi) (1-y))O3[PLZT (7/60/40)] (lead-based) and (K 0.44Na0.52Li0.04)-(Nb 0.84Ta0.1Sb0.06)O3(KNN-LT-LS) (lead-free) are found to be the top-ranked piezoelectric ceramics for transducer applications. PLZT (7/60/40) (lead-based) and 0.7Bi0.5Na0.5TiO-3-0.2Bi0.5K0.5TiO3-0.1(Bi0.5Li0.5)TiO3 (lead-free) are found to be best materials for energy storage applications.

This work examines the potential of PbZr0.53Ti0.47O3/CoFe2O4 (PZT/CFO) multi-layered nanostructures (MLNs) to achieve a giant electrocaloric effect (ECE) and enhanced pyroelectric energy harvesting. Unlike the conventional ECE, the effect of PZT/CFO MLNs is governed by dynamic magneto-electric coupling (MEC) and can be tuned by the arrangement of various ferroic layers. The ECE is investigated in the stacks of three (L3), five (L5) and nine (L9) alternating PZT and CFO layers. Intriguingly, all configurations exhibit a negative ECE, calculated using Maxwell relations, which has a high magnitude in comparison with the previously reported giant negative ECE (ΔT = 6.2 K). The maximum ECE temperature change calculated in three (L3), five (L5) and nine (L9) layers is 52.3 K, 32.4 K and 25.0 K respectively. In addition, the maximum pyroelectric energy harvesting calculated for these layers using a modified Olsen cycle is nearly four times higher than the highest reported pyroelectric energy density of 11=549 kJ m-3 cycle-1. This increase is attributed to the cumulative effect of multiple layers that induce an enhancement in the overall polarization, 1.5 times of lead zirconate titanate, and leads to abrupt polarization changes with temperature fluctuations. The present study also sheds light on material selection and the thermodynamic processes involved in the ECE and it is concluded that the refrigeration obtained from the reversed Olsen cycle is a combined effect of an isothermal entropy as well as the adiabatic temperature change.

Tri-layered PbZr0.53Ti0.47O3/CoFe2O4/PbZr0.53Ti0.47O3 (PZT/CFO/PZT) nanostructures have been reported to have the highest pyroelectric energy harvesting and electrocaloric effect. These nanostructures are magnetically active and the resultant 'giant' effects are considered to be governed by dynamic magneto-electric coupling. Therefore, it is of interest to investigate such nanostructures for thermomagnetic energy conversion and its corresponding magnetocaloric effect (MCE). In this context, the present study reveals that ferroelectric/magnetic/ferroelectric multilayered nanostructures of PZT/CFO/PZT can be used to achieve pyroelectric control over magnetization even in the absence of an applied electric field. Using the same phenomena, the coexistence of a 'giant' positive and a negative MCE is attained in the tri-layered PZT/CFO/PZT nanostructures for identical temperature ranges, but with different levels of applied magnetic field. Unlike conventional structural phase transitions based MCE effects, the present study demonstrates the possibility of obtaining a giant MCE simply by pyroelectric control of magnetism. The MCE entropy changes (ΔS(H)max = 1.5 J kg-1 K-1 for inverse MCE and 18.15 J kg-1 K-1 for positive MCE at 245 K) calculated using Maxwell equations are found to be as large as those reported for existing giant MCE systems. Moreover, our investigation of the thermomagnetic energy conversion in these nanostructures indicate that the tri-layer configuration also has a giant thermomagnetic energy conversion efficiency of 41% relative to that obtained using the Carnot cycle.

The concept of organization culture made a significant appearance in the business literature in the early 1980s. Organization culture reflects the underlying belief and value structure of an organization. Organization culture is apparently unifying and strongly appeals to management concern with projecting an image of the organization as a community of interests. Organizational culture is one of many situational variables that have emerged as pivotal in determining the success of leaders' efforts to implement change initiatives. The organizational culture plays a very significant role in making organizations get the best out of themselves. Therefore, OPTAPACE Profile (Pareek 1989), was adapted to measure the organization's culture. A total of 100 questionnaires valid questionnaires were obtained from the employees of Banks. The study determines the relationship between organizational culture and satisfaction among employees towards organizational culture. Pearson Correlation analysis was undertaken. The hypotheses are tested at the level of significance 0.05. Findings have implications for the effective and efficient management of the organization. undertaken. The hypotheses are tested at the level of significance 0.05. Findings have implications for the effective and efficient management of the organization.

This work emphasis on the competence of (100)-oriented PMN–PT buffer layered (0.68 PbMg 1/3 Nb 2/3 O 3–0.32 PbTiO 3 with Pb ( Zr 0.3 Ti 0.7) O 3/ PbO x buffer layer) and (001)-oriented PMN–PT (0.67 PbMg 1/3 Nb 2/3 O 3–0.33 PbTiO 3) for low grade thermal energy harvesting using Olsen cycle. Our analysis (based on well-reported experiments in literature) reveals that these films show colossal energy harnessing possibility. Both the films are found to have maximum harnessable energy densities (PMN–PT buffer layered: 8 MJ/m3; PMN–PT: 6.5 MJ/m3) in identical ambient conditions of 30–150°C and 0–600 kV/cm. This energy harnessing plausibility is found to be nearly five times higher than the previously reported values to date.

This work propounds the competence of epitaxial multiferroic thin-film heterostructures for low-grade thermal energy harvesting using Olsen cycle and ultra-high density capacitor applications. Our investigation (based on well-reported experiments in the literature) reveals that this class of materials shows a giant energy storage density as well as colossal energy harnessing possibilities. Indeed, the energy storage capability of these films is found to be 1.6 times the already existing giant value (alkali free glasses: 35 MJ m−3). On the other hand, the energy harnessing plausibility is found to be four orders of magnitude higher than the reported values to date.

This article demonstrates the colossal energy harvesting capability of a lead-free (Bi0.5Na0.5)0.915-(Bi0.5K0.5)0.05Ba0.02Sr0.015TiO3 ceramic using the Olsen cycle. The maximum harvestable energy density estimated for this system is found to be 1523 J/L (1523 kJ/m3) where the results are presented for extreme ambient conditions of 20–160 °C and electric fields of 0.1–4 MV/m. This estimated energy density is 1.7 times higher than the maximum reported to date for the lanthanum-doped lead zirconate titanate (thin film) system. Moreover, this study introduces a generalized and effective solid state refrigeration cycle in contrast to the ferroelectric Ericson refrigeration cycle. The cycle is based on a temperature induced polarization change on application of an unipolar electric field to ferroelectric ceramics.

This paper has considered the selection of the optimal processing parameter (sintering temperature) leading to best possible properties of K0.5Na0.5NbO3 (KNN) for electromechanical applications. Vital piezoelectric properties for such applications include the piezoelectric coupling coefficient (kp), piezoelectric coefficient (d31), Curie temperature (Tc), remanent polarization (Pr), coercive field (Ec), density (ρ), elastic compliance ( S 11 E and S 12 E ) and dielectric loss (tan δ). The weights and priority of these physical properties for KNN are calculated using the modified digital logic (MDL) method. The priority order of these properties used for the selection of optimal processing parameters is as d 31 > tan δ > S 11 E = S 12 E > T c = P r > ρ > k p > E c . The weights obtained using MDL are further incorporated with analytic hierarchy process (AHP) and VlseKriterijumska Optimisacija I Kompromisno Resenje (VIKOR) in order to determine the optimal sintering temperature for KNN. Both methods suggest that 1080 °C and 1120 °C are the most and least desirable sintering temperatures, respectively. Finally, sensitivity analysis is performed for the robustness of our results and prediction of most influential parameter in terms of sensitivity. tan δ is found to be the most sensitive property for alteration in the present ranking.