Scholarly Works, Center for Energy Harvesting Materials and Systems (CEHMS)
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- Anisotropic self-biased dual-phase low frequency magneto-mechano-electric energy harvesters with giant power densitiesPatil, Deepak Rajaram; Zhou, Yuan; Kang, Ju-Eun; Sharpes, Nathan; Jeong, Dae-Young; Kim, Yang-Do; Kim, Kee Hoon; Priya, Shashank; Ryu, Jungho (AIP Publishing, 2014-04-02)We report the physical behavior of self-biased multi-functional magneto-mechanoelectric (MME) laminates simultaneously excited by magnetic and/or mechanical vibrations. The MME laminates composed of Ni and single crystal fiber composite exhibited strong ME coupling under Hdc = 0 Oe at both low frequency and at resonance frequency. Depending on the magnetic field direction with respect to the crystal orientation, the energy harvester showed strong in-plane anisotropy in the output voltage and was found to generate open circuit output voltage of 20Vpp and power density of 59.78 mW/Oe² g² cm³ under weak magnetic field of 1 Oe and mechanical vibration of 30 mg, at frequency of 21 Hz across 1 MΩ resistance.
- Biomimetic and Live Medusae Reveal the Mechanistic Advantages of a Flexible Bell MarginColin, Sean P.; Costello, John H.; Dabiri, John O.; Villanueva, Alex A.; Blottman, John B.; Gemmell, Brad J.; Priya, Shashank (PLOS, 2012-11-07)Flexible bell margins are characteristic components of rowing medusan morphologies and are expected to contribute towards their high propulsive efficiency. However, the mechanistic basis of thrust augmentation by flexible propulsors remained unresolved, so the impact of bell margin flexibility on medusan swimming has also remained unresolved. We used biomimetic robotic jellyfish vehicles to elucidate that propulsive thrust enhancement by flexible medusan bell margins relies upon fluid dynamic interactions between entrained flows at the inflexion point of the exumbrella and flows expelled from under the bell. Coalescence of flows from these two regions resulted in enhanced fluid circulation and, therefore, thrust augmentation for flexible margins of both medusan vehicles and living medusae. Using particle image velocimetry (PIV) data we estimated pressure fields to demonstrate a mechanistic basis of enhanced flows associated with the flexible bell margin. Performance of vehicles with flexible margins was further enhanced by vortex interactions that occur during bell expansion. Hydrodynamic and performance similarities between robotic vehicles and live animals demonstrated that the propulsive advantages of flexible margins found in nature can be emulated by human-engineered propulsors. Although medusae are simple animal models for description of this process, these results may contribute towards understanding the performance of flexible margins among other animal lineages.
- Broadband/Wideband Magnetoelectric ResponsePark, Chee-Sung; Priya, Shashank (Hindawi, 2012-04-08)A broadband/wideband magnetoelectric (ME) composite offers new opportunities for sensing wide ranges of both DC and AC magnetic fields. The broadband/wideband behavior is characterized by flat ME response over a given AC frequency range and DC magnetic bias. The structure proposed in this study operates in the longitudinal-transversal (L-T) mode. In this paper, we provide information on (i) how to design broadband/wideband ME sensors and (ii) how to control the magnitude of ME response over a desired frequency and DC bias regime. A systematic study was conducted to identify the factors affecting the broadband/wideband behavior by developing experimental models and validating them against the predictions made through finite element modeling. A working prototype of the sensor with flat bands for both DC and AC magnetic field conditions was successfully obtained. These results are quite promising for practical applications such as current probe, low-frequency magnetic field sensing, and ME energy harvester.
- Colossal tunability in high frequency magnetoelectric voltage tunable inductorsYan, Yongke; Geng, Liwei D.; Tan, Yaohua; Ma, Jianhua; Zhang, Lujie; Sanghadasa, Mohan; Ngo, Khai D. T.; Ghosh, Avik W.; Wang, Yu U.; Priya, Shashank (2018-11-27)The electrical modulation of magnetization through the magnetoelectric effect provides a great opportunity for developing a new generation of tunable electrical components. Magnetoelectric voltage tunable inductors (VTIs) are designed to maximize the electric field control of permeability. In order to meet the need for power electronics, VTIs operating at high frequency with large tunability and low loss are required. Here we demonstrate magnetoelectric VTIs that exhibit remarkable high inductance tunability of over 750% up to 10 MHz, completely covering the frequency range of state-of-the-art power electronics. This breakthrough is achieved based on a concept of magnetocrystalline anisotropy (MCA) cancellation, predicted in a solid solution of nickel ferrite and cobalt ferrite through first-principles calculations. Phase field model simulations are employed to observe the domain-level strain-mediated coupling between magnetization and polarization. The model reveals small MCA facilitates the magnetic domain rotation, resulting in larger permeability sensitivity and inductance tunability.
- Combinatory Finite Element and Artificial Neural Network Model for Predicting Performance of Thermoelectric GeneratorKishore, Ravi Anant; Mahajan, Roop L.; Priya, Shashank (MDPI, 2018-08-24)Thermoelectric generators (TEGs) are rapidly becoming the mainstream technology for converting thermal energy into electrical energy. The rise in the continuous deployment of TEGs is related to advancements in materials, figure of merit, and methods for module manufacturing. However, rapid optimization techniques for TEGs have not kept pace with these advancements, which presents a challenge regarding tailoring the device architecture for varying operating conditions. Here, we address this challenge by providing artificial neural network (ANN) models that can predict TEG performance on demand. Out of the several ANN models considered for TEGs, the most efficient one consists of two hidden layers with six neurons in each layer. The model predicted TEG power with an accuracy of ±0.1 W, and TEG efficiency with an accuracy of ±0.2%. The trained ANN model required only 26.4 ms per data point for predicting TEG performance against the 6.0 minutes needed for the traditional numerical simulations.
- Compositionally Graded Multilayer Ceramic CapacitorsSong, Hyun-Cheol; Zhou, Jie E.; Maurya, Deepam; Yan, Yongke; Wang, Yu U.; Priya, Shashank (Springer Nature, 2017-09-27)Multilayer ceramic capacitors (MLCC) are widely used in consumer electronics. Here, we provide a transformative method for achieving high dielectric response and tunability over a wide temperature range through design of compositionally graded multilayer (CGML) architecture. Compositionally graded MLCCs were found to exhibit enhanced dielectric tunability (70%) along with small dielectric losses (< 2.5%) over the required temperature ranges specified in the standard industrial classifications. The compositional grading resulted in generation of internal bias field which enhanced the tunability due to increased nonlinearity. The electric field tunability of MLCCs provides an important avenue for design of miniature filters and power converters.
- Correlation between tunability and anisotropy in magnetoelectric voltage tunable inductor (VTI)Yan, Yongke; Geng, Liwei D.; Zhang, Lujie; Gao, Xiangyu; Gollapudi, Sreenivasulu; Song, Hyun-Cheol; Dong, Shuxiang; Sanghadasa, Mohan; Ngo, Khai D. T.; Wang, Yu U.; Priya, Shashank (Springer Nature, 2017-11-22)Electric field modulation of magnetic properties via magnetoelectric coupling in composite materials is of fundamental and technological importance for realizing tunable energy efficient electronics. Here we provide foundational analysis on magnetoelectric voltage tunable inductor (VTI) that exhibits extremely large inductance tunability of up to 1150% under moderate electric fields. This field dependence of inductance arises from the change of permeability, which correlates with the stress dependence of magnetic anisotropy. Through combination of analytical models that were validated by experimental results, comprehensive understanding of various anisotropies on the tunability of VTI is provided. Results indicate that inclusion of magnetic materials with low magnetocrystalline anisotropy is one of the most effective ways to achieve high VTI tunability. This study opens pathway towards design of tunable circuit components that exhibit field-dependent electronic behavior.
- Cyanea capillata Bell Kinematics Analysis through Corrected In Situ Imaging and Modeling Using Strategic Discretization TechniquesVillanueva, Alex A.; Priya, Shashank (PLOS, 2014-12-26)Obtaining accurate kinematic data of animals is essential for many biological studies and bio-inspired engineering. Many animals, however, are either too large or too delicate to transport to controlled environments where accurate kinematic data can be easily obtained. Often, in situ recordings are the only means available but are often subject to multi-axis motion and relative magnification changes with time leading to large discrepancies in the animal kinematics. Techniques to compensate for these artifacts were applied to a large jellyfish, Cyanea capillata, freely swimming in ocean waters. The bell kinematics were captured by digitizing exumbrella profiles for two full swimming cycles. Magnification was accounted for by tracking a reference point on the ocean floor and by observing the C. capillata exumbrella arclength in order to have a constant scale through the swimming cycles. A linear fit of the top bell section was used to find the body angle with respect to the camera coordinate system. Bell margin trajectories over two swimming cycles confirmed the accuracy of the correction techniques. The corrected profiles were filtered and interpolated to provide a set of time-dependent points along the bell. Discrete models of the exumbrella were used to analyze the bell kinematics. Exumbrella discretization was conducted using three different methods. Fourier series were fitted to the discretized models and subsequently used to analyze the bell kinematics of the C. capillata. The analysis showed that the bell did not deform uniformly over time with different segments lagging behind each other. Looping of the bell trajectory between contraction and relaxation was also present through most of the exumbrella. The bell margin had the largest looping with an outer path during contraction and inner path during relaxation. The subumbrella volume was approximated based on the exumbrella kinematics and was found to increase during contraction.
- Defect and adsorbate induced ferromagnetic spin-order in magnesium oxide nanocrystallitesKumar, Ashok; Kumar, Jitendra; Priya, Shashank (AIP Publishing, 2012-05-01)We report the correlation between d(0) ferromagnetism, photoluminescence (PL), and adsorbed hydrogen (H-) species in magnesium oxide (MgO) nanocrystallites. Our study suggests that the oxygen vacancies, namely singly ionized anionic vacancies (F+) and dimers (F-2(2+)) induce characteristic photoluminescence and the room-temperature ferromagnetic spin-order. Nanocrystallites with low population of oxygen vacancies have revealed diamagnetic behavior. Intriguingly, on adsorption of hydrogen (H-) species in the MgO nanocrystallites, ferromagnetic behavior was either enhanced (in the case of highly oxygen deficient nanocrystallites) or begun to percolate (in the case of nanocrystallite with low population density of oxygen vacancies). (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4712058]
- Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser StructureHudait, Mantu K.; Murphy-Armando, Felipe; Saladukha, Dzianis; Clavel, Michael B.; Goley, Patrick S.; Maurya, Deepam; Bhattacharya, Shuvodip; Ochalski, Tomasz J. (American Chemical Society, 2021-10-14)Strain and band gap engineered epitaxial germanium (ϵ-Ge) quantum-well (QW) laser structures were investigated on GaAs substrates theoretically and experimentally for the first time. In this design, we exploit the ability of an InGaAs layer to simultaneously provide tensile strain in Ge (0.7-1.96%) and sufficient optical and carrier confinement. The direct band-to-band gain, threshold current density (Jth), and loss mechanisms that dominate in the ϵ-Ge QW laser structure were calculated using first-principles-based 30-band k·p electronic structure theory, at injected carrier concentrations from 3 × 1018 to 9 × 1019 cm-3. The higher strain in the ϵ-Ge QW increases the gain at higher wavelengths; however, a decreasing thickness is required by higher strain due to critical layer thickness for avoiding strain relaxation. In addition, we predict that a Jth of 300 A/cm2 can be reduced to <10 A/cm2 by increasing strain from 0.2% to 1.96% in ϵ-Ge lasing media. The measured room-temperature photoluminescence spectroscopy demonstrated direct band gap optical emission, from the conduction band at the Γ-valley to heavy-hole (0.6609 eV) from 1.6% tensile-strained Ge/In0.24Ga0.76As heterostructure grown by molecular beam epitaxy, is in agreement with the value calculated using 30-band k·p theory. The detailed plan-view transmission electron microscopic (TEM) analysis of 0.7% and 1.2% tensile-strained ϵ-Ge/InGaAs structures exhibited well-controlled dislocations within each ϵ-Ge layer. The measured dislocation density is below 4 × 106 cm-2 for the 1.2% ϵ-Ge layer, which is an upper bound, suggesting the superior ϵ-Ge material quality. Structural analysis of the experimentally realistic 1.95% biaxially strained In0.28Ga0.72As/13 nm ϵ-Ge/In0.28Ga0.72As QW structure demonstrated a strained Ge/In0.28Ga0.72As heterointerface with minimal relaxation using X-ray and cross-sectional TEM analysis. Therefore, our monolithic integration of a strained Ge QW laser structure on GaAs and ultimately the transfer of the process to the Si substrate via an InGa(Al)As/III-V buffer architecture would provide a significant step toward photonic technology based on strained Ge on a Si platform.
- Direct and converse effect in magnetoelectric laminate compositesCho, Kyung-Hoon; Priya, Shashank (AIP Publishing, 2011-06-01)In this letter, we analyze the direct and converse effect in laminate composites of magnetostrictive and piezoelectric materials. Our results deterministically show that direct magnetoelectric (ME) effect is maximized at antiresonance frequency while the converse ME effect is maximized at resonance frequency of the laminate composite. We explain this phenomenon by using piezoelectric constitutive equations and combining it with resonance boundary conditions. The dominant factor controlling the position of peak ME coefficient was found to be frequency dependent capacitance of piezoelectric layer. This study will provide guidance toward the development of magnetic field sensors based on direct effect and communication components based on converse effect. (C) 2011 American Institute of Physics. [doi:10.1063/1.3584863]
- Discovery and ramifications of incidental Magnéli phase generation and release from industrial coal-burningYang, Yi; Chen, Bo; Hower, James C.; Schindler, Michael; Winkler, Christopher; Brandt, Jessica E.; Di Giulio, Richard T.; Ge, Jianping; Liu, Min; Fu, Yuhao; Zhang, Lijun; Chen, Yu-ru; Priya, Shashank; Hochella, Michael F. Jr. (Nature Publishing Group, 2017-01-12)Coal, as one of the most economic and abundant energy sources, remains the leading fuel for producing electricity worldwide. Yet, burning coal produces more global warming CO2 relative to all other fossil fuels, and it is a major contributor to atmospheric particulate matter known to have a deleterious respiratory and cardiovascular impact in humans, especially in China and India. Here we have discovered that burning coal also produces large quantities of otherwise rare Magneli phases (Ti; x; O2x–1 with 4 ≤ x ≤ 9) from TiO2 minerals naturally present in coal. This provides a new tracer for tracking solid-state emissions worldwide from industrial coal-burning. In its first toxicity testing, we have also shown that nanoscale Magneli phases have potential toxicity pathways that are not photoactive like TiO2 phases, but instead seem to be biologically active without photostimulation. In the future, these phases should be thoroughly tested for their toxicity in the human lung. Solid-state emissions from coal burning remain an environmental concern. Here, the authors have found that TiO2 minerals present in coal are converted into titanium suboxides during burning, and initial biotoxicity screening suggests that further testing is needed to look into human lung consequences.
- Dual-phase self-biased magnetoelectric energy harvesterZhou, Yuan; Apo, Daniel J.; Priya, Shashank (AIP Publishing, 2013-11-01)We report a magnetoelectric energy harvester structure that can simultaneously scavenge magnetic and vibration energy in the absence of DC magnetic field. The structure consisted of a piezoelectric macro-fiber composite bonded to a Ni cantilever. Large magnetoelectric coefficient similar to 50 V/cm Oe and power density similar to 4.5 mW/cm(3) (1 g acceleration) were observed at the resonance frequency. An additive effect was realized when the harvester operated under dual-phase mode. The increase in voltage output at the first three resonance frequencies under dual-phase mode was found to be 2.4%, 35.5%, and 360.7%. These results present significant advancement toward high energy density multimode energy harvesting system. (C) 2013 AIP Publishing LLC.
- Effect of intensive and extensive loss factors on the dynamic response of magnetoelectric laminatesCho, Kyung-Hoon; Park, Chee-Sung; Priya, Shashank (AIP Publishing, 2010-11-01)We report the correlation between intensive and extensive losses in piezoelectric materials with the frequency dependent response of layered magnetoelectric (ME) composites. Three different piezoelectric compositions were synthesized to achieve varying loss characteristics allowing a systematic interpretation of changes in ME coupling in terms of loss components. We clearly demonstrate that intensive dielectric and piezoelectric loss play an important role in controlling the ME sensitivity of layered composites in sub-resonance low frequency range while extensive mechanical loss is dominant factor at resonance condition. Further, the maximum in ME response is obtained at antiresonance frequency of piezoelectrics. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3511285]
- Electromechanical behavior of 001 -textured Pb(Mg1/3Nb2/3)O-3-PbTiO3 ceramicsYan, Yongke; Wang, Yu. U.; Priya, Shashank (AIP Publishing, 2012-05-01)[001]-textured Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PMN-PT) ceramics were synthesized by using templated grain growth method. Significantly high [001] texture degree corresponding to 0.98 Lotgering factor was achieved at 1 vol. % BaTiO3 template. Electromechanical properties for [001]-textured PMN-PT ceramics with 1 vol. % BaTiO3 were found to be d(33) = 1000 pC/N, d(31) = 371 pC/N, epsilon(r) 2591, and tan delta = similar to 0.6%. Elastoelectric composite based modeling results showed that higher volume fraction of template reduces the overall dielectric constant and thus has adverse effect on the piezoelectric response. Clamping effect was modeled by deriving the changes in free energy as a function of applied electric field and microstructural boundary condition. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4712563]
- Energy band alignment of atomic layer deposited HfO2 on epitaxial (110)Ge grown by molecular beam epitaxyHudait, Mantu K.; Zhu, Y.; Maurya, Deepam; Priya, Shashank (AIP Publishing, 2013-03-01)The band alignment properties of atomic layer HfO2 film deposited on epitaxial (110)Ge, grown by molecular beam epitaxy, was investigated using x-ray photoelectron spectroscopy. The cross-sectional transmission electron microscopy exhibited a sharp interface between the (110)Ge epilayer and the HfO2 film. The measured valence band offset value of HfO2 relative to (110)Ge was 2.28 +/- 0.05 eV. The extracted conduction band offset value was 2.66 +/- 0.1 eV using the bandgaps of HfO2 of 5.61 eV and Ge bandgap of 0.67 eV. These band offset parameters and the interface chemical properties of HfO2/(110)Ge system are of tremendous importance for the design of future high hole mobility and low-power Ge-based metal-oxide transistor devices. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794838]
- Enhanced piezoelectric performance from carbon fluoropolymer nanocompositesBaur, Cary; DiMaio, Jeffrey R.; McAllister, Elliot; Hossini, Reza; Wagener, Earl; Ballato, John; Priya, Shashank; Ballato, Arthur; Smith, Dennis W. Jr. (American Institute of Physics, 2012-12-15)The piezoelectric performance of polyvinylidene fluoride (PVDF) is shown to double through the controlled incorporation of carbon nanomaterial. Specifically, PVDF composites containing carbon fullerenes (C-60) and single-walled carbon nanotubes (SWNT) are fabricated over a range of compositions and optimized for their Young's modulus, dielectric constant, and d(31) piezoelectric coefficient. Thermally stimulated current measurements show a large increase in internal charge and polarization in the composites over pure PVDF. The electromechanical coupling coefficients (k(31)) at optimal loading levels are found to be 1.84 and 2 times greater than pure PVDF for the PVDF-C-60 and PVDF-SWNT composites, respectively. Such property-enhanced nanocomposites could have significant benefit to electromechanical systems employed for structural sensing, energy scavenging, sonar, and biomedical imaging. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768923]
- Enhanced piezoelectricity and nature of electric-field induced structural phase transformation in textured lead-free piezoelectric Na0.5Bi0.5TiO3-BaTiO3 ceramicsMaurya, Deepam; Pramanick, Abhijit; An, Ke; Priya, Shashank (AIP Publishing, 2012-04-01)This letter provides a comparative description of the properties of textured and randomly oriented poly-crystalline lead-free piezoelectric 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO(3) (NBT-BT) ceramics. A high longitudinal piezoelectric constant of (d(33)) similar to 322 pC/N was obtained in (001)(PC) textured NBT-7BT ceramics, which is almost similar to 2x times the d(33) coefficient reported for randomly oriented ceramics of the same composition. In situ neutron diffraction experiments revealed that characteristically different structural responses are induced in textured and randomly oriented NBT-BT ceramics upon application of electric fields (E), which are likely related to the varying coherence lengths of polar nanoregions and internal stresses induced by domain switching. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4709404]
- Enhanced torsional actuation and stress coupling in Mn-modified 0.93(Na0.5Bi0.5TiO3)-0.07BaTiO(3) lead-free piezoceramic systemBerik, Pelin; Maurya, Deepam; Kumar, Prashant; Kang, Min-Gyu; Priya, Shashank (Taylor & Francis, 2017-01-01)
- Ferroelectric properties and dynamic scaling of < 100 > oriented (K0.5Na0.5)NbO3 single crystalsGupta, Sanjay; Priya, Shashank (AIP Publishing, 2011-06-01)In this letter, we report the dielectric and ferroelectric (FE) characteristics of potassium sodium niobate (K0.5Na0.5NbO3) single crystals grown by flux method. Orientation analysis of as-grown cubical-shaped crystals was conducted by electron backscattered diffraction technique revealing the < 100 > crystallographic orientation of two opposing major faces. Annealed crystals were found to exhibit FE orthorhombic to FE tetragonal transition temperature of 200 degrees C and Curie temperature of 407 degrees C. Poled < 100 > oriented crystals had longitudinal piezoelectric constant of 148 pC/N. Dielectric measurement as a function of temperature was conducted to determine the second order parameter in Gibbs free energy expansion. Dynamic hysteresis analysis on these crystals showed the power law relations to be of the form < A > proportional to f(0.47Eo-0.85)E(o)(1.45f0.14) and < A > proportional to f(0.04)E(o) below and above the coercive field. (C) 2011 American Institute of Physics. [doi:10.1063/1.3600058]