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Palneedi, Haribabu,Maurya, Deepam,Geng, Liwei D.,Song, Hyun-Cheol,Hwang, Geon-Tae,Peddigari, Mahesh,Annapureddy, Venkateswarlu,Song, Kyung,Oh, Yoon Seok,Yang, Su-Chul,Wang, Yu U.,Priya, Shashank,Ryu, American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.13
<P>Enhanced and self-biased magnetoelectric (ME) coupling is demonstrated in a laminate heterostructure comprising 4 μm-thick Pb(Zr,Ti)O<SUB>3</SUB> (PZT) film deposited on 50 μm-thick flexible nickel (Ni) foil. A unique fabrication approach, combining room temperature deposition of PZT film by granule spray in vacuum (GSV) process and localized thermal treatment of the film by laser radiation, is utilized. This approach addresses the challenges in integrating ceramic films on metal substrates, which is often limited by the interfacial chemical reactions occurring at high processing temperatures. Laser-induced crystallinity improvement in the PZT thick film led to enhanced dielectric, ferroelectric, and magnetoelectric properties of the PZT/Ni composite. A high self-biased ME response on the order of 3.15 V/cm·Oe was obtained from the laser-annealed PZT/Ni film heterostructure. This value corresponds to a ∼2000% increment from the ME response (0.16 V/cm·Oe) measured from the as-deposited PZT/Ni sample. This result is also one of the highest reported values among similar ME composite systems. The tunability of self-biased ME coupling in PZT/Ni composite has been found to be related to the demagnetization field in Ni, strain mismatch between PZT and Ni, and flexural moment of the laminate structure. The phase-field model provides quantitative insight into these factors and illustrates their contributions toward the observed self-biased ME response. The results present a viable pathway toward designing and integrating ME components for a new generation of miniaturized tunable electronic devices.</P> [FIG OMISSION]</BR>
Palneedi, Haribabu,Na, Suok-Min,Hwang, Geon-Tae,Peddigari, Mahesh,Shin, Kwang Woo,Kim, Kee Hoon,Ryu, Jungho Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.765 No.-
<P><B>Abstract</B></P> <P>In this study, it is proposed and demonstrated that highly tunable magnetoelectric (ME) response can be achieved from magnetostrictive/piezoelectric laminate composites by integrating the effects of size variation and piezoelectric anisotropy. Tri-layered, rectangular ME composites with different aspect ratios were prepared using a magnetostrictive Fe-Ga alloy and a (011) oriented Pb(Mg<SUB>1/3</SUB>Nb<SUB>2/3</SUB>)O<SUB>3</SUB>-Pb(Zr,Ti)O<SUB>3</SUB> (PMN-PZT) piezoelectric single crystal. ME coefficients in the range of 0.25–2.2 V/cm·Oe and 2–75 V/cm·Oe in the off-resonance and resonance mode, respectively, were obtained from the composites. Magnetic sensitivity of the ME composites followed a similar trend in variation as that of their ME response with respect to the laminate size and applied magnetic field direction. The tunability of the ME response of the composites was correlated with the size dependent demagnetization and magnetic flux density distribution in the Fe-Ga alloy and direction dependent piezoelectric properties of the (011) PMN-PZT single crystal. In both the off-resonance and resonance modes, an order of magnitude large tunability could be attained in the ME coefficient of the composites. Such a highly tunable ME response will facilitate the development of ME based devices with controllable functionality.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly tunable magnetoelectric response from magnetostrictive/piezoelectric laminate composites. </LI> <LI> Integration of the effects of laminate size variation and piezoelectric anisotropy. </LI> <LI> Size dependent demagnetization and magnetic flux density distribution in the magnetostrictive alloy. </LI> <LI> Direction dependent piezoelectric properties of the oriented single crystal. </LI> </UL> </P>
Linear and Nonlinear Dielectric Ceramics for High-Power Energy Storage Capacitor Applications
Peddigari, Mahesh,Palneedi, Haribabu,Hwang, Geon-Tae,Ryu, Jungho The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.1
Dielectric materials with inherently high power densities and fast discharge rates are particularly suitable for pulsed power capacitors. The ongoing multifaceted efforts on developing these capacitors are focused on improving their energy density and storage efficiency, as well as ensuring their reliable operation over long periods, including under harsh environments. This review article summarizes the studies that have been conducted to date on the development of high-performance dielectric ceramics for employment in pulsed power capacitors. The energy storage characteristics of various lead-based and lead-free ceramics belonging to linear and nonlinear dielectrics are discussed. Various strategies such as mechanical confinement, self-confinement, core-shell structuring, glass incorporation, chemical modifications, and special sintering routes have been adopted to tailor the electrical properties and energy storage performances of dielectric ceramics. In addition, this review article highlights the challenges and opportunities associated with the development of pulsed power capacitors.
Annapureddy, Venkateswarlu,Palneedi, Haribabu,Yoon, Woon-Ha,Park, Dong-Soo,Choi, Jong-Jin,Hahn, Byung-Dong,Ahn, Cheol-Woo,Kim, Jong-Woo,Jeong, Dae-Yong,Ryu, Jungho Elsevier Sequoia 2017 Sensors and actuators. A Physical Vol.260 No.-
<P><B>Abstract</B></P> <P>This study reports of an <I>ac</I> magnetic field sensor with pT/√Hz sensitivity based on self-biased magnetoelectric composites made using piezoelectric Pb(Mg<SUB>1/3</SUB>Nb<SUB>2/3</SUB>)O<SUB>3</SUB>-PbZrO<SUB>3</SUB>-PbTiO<SUB>3</SUB> (PMN-PZT) single crystals in macro-fiber form and a magnetostrictive Ni plate. Variation in the loss properties of the PMN-PZT single crystals resulted in a substantial change in the magnetic field sensitivity of the ME based sensors. It was found that the loss factor of the piezoelectric layer was one of the key parameters affecting the magnetic field sensitivity. The ME composite sensor structure employing low-loss piezoelectric single crystals achieved a limit of detection (LOD) in the range of a few pT/√Hz at its resonance frequency (500Hz). This magnitude of sensitivity is much higher than that offered bycommercially available magnetic sensors based on the giant magnetoresistance (GMR) effect or Hall-effect.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Magnetic sensors are designed using self-biased magnetoelectric composites made of piezoelectric PMN-PZT single crystals and magnetostrictive Ni. </LI> <LI> A greatly enhanced magnetic sensitivity in the range of pT/√Hz is obtained from the ME composite based sensor, which is better than that of commercial magnetic sensors. </LI> <LI> The loss factor of the piezoelectric layer is an important parameter affecting the magnetic field sensitivity. </LI> </UL> </P>
Peddigari, Mahesh,Palneedi, Haribabu,Hwang, Geon-Tae,Lim, Kyung Won,Kim, Ga-Yeon,Jeong, Dae-Yong,Ryu, Jungho American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.24
<P>Dielectric ceramic film capacitors, which store energy in the form of electric polarization, are promising for miniature pulsed power electronic device applications. For a superior energy storage performance of the capacitors, large recoverable energy density, along with high efficiency, high power density, fast charge/discharge rate, and good thermal/fatigue stability, is desired. Herein, we present highly dense lead-free 0.942[Na<SUB>0.535</SUB>K<SUB>0.480</SUB>NbO<SUB>3</SUB>]-0.058LiNbO<SUB>3</SUB> (KNNLN) ferroelectric ceramic thick films (∼5 μm) demonstrating remarkable energy storage performance. The nanocrystalline KNNLN thick film fabricated by aerosol deposition (AD) process and annealed at 600 °C displayed a quasi-relaxor ferroelectric behavior, which is in contrast to the typical ferroelectric nature of the KNNLN ceramic in its bulk form. The AD film exhibited a large recoverable energy density of 23.4 J/cm<SUP>3</SUP>, with an efficiency of over 70% under the electric field of 1400 kV/cm. Besides, an ultrahigh power density of 38.8 MW/cm<SUP>3</SUP> together with a fast discharge speed of 0.45 μs, good fatigue endurance (up to 10<SUP>6</SUP> cycles), and thermal stability in a wide temperature range of 20-160 °C was also observed. Using the AD process, we could make a highly dense microstructure of the film containing nano-sized grains, which gave rise to the quasi-relaxor ferroelectric characteristics and the remarkable energy storage properties.</P> [FIG OMISSION]</BR>
Hwang, Geon-Tae,Palneedi, Haribabu,Jung, Byung Mun,Kwon, Suk Jin,Peddigari, Mahesh,Min, Yuho,Kim, Jong-Woo,Ahn, Cheol-Woo,Choi, Jong-Jin,Hahn, Byung-Dong,Choi, Joon-Hwan,Yoon, Woon-Ha,Park, Dong-Soo,L American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.38
<P>We report the effect of epoxy adhesion layers with different mechanical or physical property on a magnetoelectric (ME) composite laminate composed of FeBSi alloy (Metglas)/single-crystal Pb(Mg<SUB>1/3</SUB>Nb<SUB>2/3</SUB>)O<SUB>3</SUB>-Pb(Zr,Ti)O<SUB>3</SUB>/Metglas to achieve an improved ME conversion performance. Through theoretical simulation, it was revealed that the Young’s modulus and the thickness of interfacial adhesives were major parameters that influence the conversion efficiency in ME composites. In the experimental evaluation, we utilized three epoxy materials with a distinct Young’s modulus and adjusted the average thickness of the adhesion layers to optimize the ME conversion. The experimental results show that a thin epoxy layer with a high Young’s modulus provided the best performance in the inorganic-based ME conversion process. By tailoring the interfacial adhesion property, the ME laminate generated a high conversion coefficient of 328.8 V/(cm Oe), with a mechanical quality factor of 132.0 at the resonance mode. Moreover, we demonstrated a highly sensitive alternating current magnetic field sensor that had a detection resolution below 10 pT. The optimization of the epoxy layers in the ME laminate composite provided significant enhancement of the ME response in a simple manner.</P> [FIG OMISSION]</BR>
Annapureddy, Venkateswarlu,Kang, Joo-Hee,Palneedi, Haribabu,Kim, Jong-Woo,Ahn, Cheol-Woo,Choi, Si-Young,Johnson, Scooter David,Ryu, Jungho Elsevier Science Publishers 2017 Journal of the European Ceramic Society Vol. No.
<P><B>Abstract</B></P> <P>In this report a simple and low-cost technique for growing highly textured barium hexaferrite ceramics without the need for flux or seed crystals to achieve grain orientation is demonstrated. Plate-like shaped barium hexaferrite particles were synthesized using a solid-state reaction process and then aligned under a weak magnetic field, followed by uniaxial compaction. The aligned hexaferrite particles appear to serve as seeds, forming textured grains during sintering. The development of texture was verified by X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and vibration sample magnetometer (VSM) measurements. The prepared high-quality hexaferrite ceramics exhibited good anisotropic magnetic properties, comparable to those of single crystal counterparts. A mechanism for the formation of the self-textured grain growth of the barium hexaferrite ceramics, which involves grain boundary and lattice diffusion and interface reaction processes, is proposed.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Dual-stimulus magnetoelectric energy harvesting
Chu, Zhaoqiang,Annapureddy, Venkateswarlu,PourhosseiniAsl, MohammadJavad,Palneedi, Haribabu,Ryu, Jungho,Dong, Shuxiang Cambridge University Press (Materials Research Soc 2018 MRS bulletin Vol.43 No.3
<▼1><B>Abstract</B><P/></▼1><▼2><P>Harvesting energy from otherwise wasted resources has been intensively investigated as a promising technology especially for enabling the deployment of autonomous wireless-sensor networks for the Internet of Things. Multi-stimulus energy harvesting, simultaneously from different energy sources, provides an attractive opportunity to amplify the power density of harvesters, thereby extending their potential for self-powered devices. In this article, we review recent and ongoing research efforts aimed at enhancing the energy-harvesting performance of magnetoelectric (ME) composite harvesters employing dual stimuli, mechanical vibrations, and magnetic fields. After a brief introduction to vibration, magnetic field, and dual-mode energy harvesting, we survey the key materials utilized for ME energy harvesting. We then focus on progress in this area and discuss relevant ideas to realize electromechanical and magnetoelectric coupling for harvesting energy from mechanical vibrations and magnetic fields simultaneously. We provide perspectives and future directions as well.</P></▼2>
Lead-free piezoelectric materials and composites for high power density energy harvesting
Maurya, Deepam,Peddigari, Mahesh,Kang, Min-Gyu,Geng, Liwei D.,Sharpes, Nathan,Annapureddy, Venkateswarlu,Palneedi, Haribabu,Sriramdas, Rammohan,Yan, Yongke,Song, Hyun-Cheol,Wang, Yu U.,Ryu, Jungho,Pri Published for the Materials Research Society by th 2018 Journal of materials research Vol.33 No.16
<▼1><B>Abstract</B><P/></▼1><▼2><P>In the emerging era of Internet of Things (IoT), power sources for wireless sensor nodes in conjunction with efficient and secure wireless data transfer are required. Energy harvesting technologies are promising solution toward meeting the requirements for sustainable power sources for the IoT. In this review, we focus on approaches for harvesting stray vibrations and magnetic field due to their abundance in the environment. Piezoelectric materials and piezoelectric-magnetostrictive [magnetoelectric (ME)] composites can be used to harvest vibration and magnetic field, respectively. Currently, such harvesters use modified lead zirconate titanate (or lead-based) piezoelectric materials and ME composites. However, environmental concerns and government regulations require the development of a suitable lead-free replacement for lead-based piezoelectric materials. In the past decade, several lead-free piezoelectric compositions have been developed and demonstrated with promising piezoelectric response. This paper reviews the significant results reported on lead-free piezoelectric materials with respect to high-density energy harvesting, covering novel processing techniques for improving the piezoelectric response and temperature stability. The review of the state-of-the-art studies on vibration and magnetic field harvesting is provided and the results are used to discuss various strategies for designing high-performance energy harvesting devices.</P></▼2>