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Full-Text Articles in Engineering

Magnetic And Microwave Properties Of Cofe/Ptmn/Cofe Multilayer Films, C. Pettiford, A. Zeltser, S. Yoon, V. Harris, C. Vittoria, N. Sun Aug 2013

Magnetic And Microwave Properties Of Cofe/Ptmn/Cofe Multilayer Films, C. Pettiford, A. Zeltser, S. Yoon, V. Harris, C. Vittoria, N. Sun

Nian X. Sun

CoFe/PtMn/CoFe films were deposited on seed layers of Ru or NiFeCr with CoFe film compositions being either Co-10 at. %Fe or Co-16 at. %Fe. Eight periods of the CoFe/PtMn/CoFe trilayers were also prepared. The magnetic properties and ferromagnetic resonance (FMR) of these films were characterized with vibrating-sample magnetometer, and field-sweep FMR system at X band (∽9.5 GHz). The Ru-seeded CoFe/PtMn/CoFe sandwich films show excellent magnetic softness with a low hard axis coercivity of 2-4 Oe, an easy axis Mr/Ms of >98%, and a significantly enhanced in-plane anisotropy of 57-123 Oe when CoFe layer thickness is above 200 …


Room Temperature Magnetism In Semiconducting Films Of Zno Doped With Ferric Ions, S. D. Yoon, Y. J. Chen, D. Heiman, A. Yang, N. Sun, C. Vittoria, V. G. Harris Aug 2013

Room Temperature Magnetism In Semiconducting Films Of Zno Doped With Ferric Ions, S. D. Yoon, Y. J. Chen, D. Heiman, A. Yang, N. Sun, C. Vittoria, V. G. Harris

Nian X. Sun

Films consisting of Zn₁₋ₓFeₓO were prepared by alternating-target laser ablation deposition. The Fe doping levels ranged from x=0.016 to 0.125 at. %. X-ray diffraction and energy dispersive x-ray spectroscopy measurements showed only (002n) reflections of the ZnO host and confirmation of the Fe concentration, respectively. For films grown on (001) Al₂O₃ at 300 K, room temperature average saturation magnetization, < 4πMs >, measured from superconducting quantum interference device (SQUID) hysteresis loops for x=0.125 ± 0.025 was 172 G. Although SQUID measurements were sensitive to the average value of the saturation magnetization, ferrimagnetic resonance measurements appeared to be sensitive only to the saturation …


Single Crystal Fe Films Grown On Ge(001) Substrates By Magnetron Sputtering, J. Lou, A. Daigle, L. Chen, Y. Q. Wu, V. G. Harris, C. Vittoria, N. X. Sun Aug 2013

Single Crystal Fe Films Grown On Ge(001) Substrates By Magnetron Sputtering, J. Lou, A. Daigle, L. Chen, Y. Q. Wu, V. G. Harris, C. Vittoria, N. X. Sun

Nian X. Sun

Single crystal Fe films were grown on Ge (001) substrates by using dc magnetron sputtering. It was found that the microstructures and magnetic properties of Fe films on Ge substrates were strongly dependent upon the substrate temperature during the deposition process. There existed a narrow substrate temperature window of 125 ± 25°C for achieving single crystal Fe film on Ge. Lower substrate temperature led to polycrystalline Fe films due to limited mobility of Fe atoms, while higher substrate temperatures resulted in amorphous Fe-Ge alloy due to severe interdiffusion.


Structure And Magnetism Of Nanocrystalline Exchange-Coupled (Ni₀.₆₇Co₀.₂₅Fe₀.₀₈)₈₉₋ₓzr₇B₄Cuₓ (X=0,1) Films, S. Joshi, S. D. Yoon, A. Yang, N. X. Sun, C. Vittoria, V. G. Harris, R. Goswami, M. Willard, N. Shi Aug 2013

Structure And Magnetism Of Nanocrystalline Exchange-Coupled (Ni₀.₆₇Co₀.₂₅Fe₀.₀₈)₈₉₋ₓzr₇B₄Cuₓ (X=0,1) Films, S. Joshi, S. D. Yoon, A. Yang, N. X. Sun, C. Vittoria, V. G. Harris, R. Goswami, M. Willard, N. Shi

Nian X. Sun

Structural and magnetic characterizations of nanocrystalline films of (Ni₀.₆₇Co₀.₂₅Fe₀.₀₈)₈₉₋ₓZr₇B₄Cuₓ (x=0,1) alloys are reported. The films were grown on quartz substrates using pulsed laser deposition from homogeneous targets of the above compositions at substrate temperatures ranging from ambient to 600°C. Structural properties were measured by x-ray diffraction, atomic force microscopy, and transmission electron microscopy, whereas the magnetic properties were measured by vibrating sample magnetometry and ferromagnetic resonance. The resulting films exist as a two phase alloy with face-centered-cubic metallic grains suspended in an amorphous matrix. For both the x=1 and x=0 alloys, the softest magnetic properties (coercivity Hc < 0.5 Oe, 4πMs …


A Quantitative Model For The Nonlinear Response Of Fluxgate Magnetometers, A. L. Geiler, V. G. Harris, C. Vittoria, N. X. Sun Aug 2013

A Quantitative Model For The Nonlinear Response Of Fluxgate Magnetometers, A. L. Geiler, V. G. Harris, C. Vittoria, N. X. Sun

Nian X. Sun

An analytical nonlinear hysteresis model was developed to describe the hysteresis loops of different magnetic materials, which was capable of fitting Permalloy films as an example. As a case study this model was applied in the sensitivity analysis of the fluxgate magnetometers where accurately capturing the nonlinear behavior of the magnetic core is crucial. Straightforward analytical equation of the output voltage signal as well as its harmonic decomposition was obtained for the fluxgate magnetometer as a function of hysteresis loop parameters. Sensitivity values predicted by the model were found to be consistent with the measured values published previously. The model …


Microwave Tunability In A Gaas-Based Multiferroic Heterostructure: Co₂Mnal/Gaas/Pmn-Pt, Y. Chen, J. Gao, M. Liu, S. D. Yoon, A. L. Geiler, M. Nedoroscik, D. Heiman, N. X. Sun, C. Vittoria, V. G. Harris Aug 2013

Microwave Tunability In A Gaas-Based Multiferroic Heterostructure: Co₂Mnal/Gaas/Pmn-Pt, Y. Chen, J. Gao, M. Liu, S. D. Yoon, A. L. Geiler, M. Nedoroscik, D. Heiman, N. X. Sun, C. Vittoria, V. G. Harris

Nian X. Sun

A strong magnetoelectric (ME) interaction is presented in a magnetostrictive-semiconductor-piezoelectric heterostructure that consists of the Huesler alloy, Co₂MnAl, GaAs, and lead magnesium niobate-lead titanate (PMN-PT). The laminated Co₂MnAl/GaAs/PMN-PT structure, having a thickness of 19 nm/180 μm/500 μm, demonstrates a ferromagnetic resonance (FMR) field shift of 28 Oe with an external electric field of 200 V across the PMN-PT substrate. This corresponds to a resonance frequency shift of similar to 125 MHz at X-band. It yields a large ME coupling (7 Oe cm/kV) and microwave tunability (similar to 32 MHz/kV cm⁻¹), compared to other trilayer multiferroic composite structures. In addition, static …


Microwave, Magnetic, And Structural Properties Of Nanocrystalline Exchange-Coupled Ni₁₁Co₁₁Fe₆₆Zr₇B₄Cu₁ Films For High Frequency Applications, S. D. Yoon, A. K. Baraskar, A. Geiler, A. Yang, C. Pettiford, N. X. Sun, R. Goswami, M. A. Willard, C. Vittoria, V. G. Harris Aug 2013

Microwave, Magnetic, And Structural Properties Of Nanocrystalline Exchange-Coupled Ni₁₁Co₁₁Fe₆₆Zr₇B₄Cu₁ Films For High Frequency Applications, S. D. Yoon, A. K. Baraskar, A. Geiler, A. Yang, C. Pettiford, N. X. Sun, R. Goswami, M. A. Willard, C. Vittoria, V. G. Harris

Nian X. Sun

Nanocrystalline structured films of the alloy Ni₁₁Co₁₁Fe₆₆Zr₇B₄Cu₁ were deposited by pulsed laser ablation deposition onto fused quartz substrates. A substrate temperature of 300°C was found to produce films consisting of body-centered-cubic (bcc) metallic grains suspended in an amorphous matrix. The bcc grain size ranged from 5 - 8 nm for substrate temperatures up to 300°C. Measured values of coercivity were consistently below 4 Oe for films having a saturation magnetization, as 4π Ms, of ∽16 kG with in- plane uniaxial anisotropy fields of 25 to 30 Oe. The ferromagnetic resonance peak- to- peak derivative linewidth was measured to be 34 …


Voltage Impulse Induced Bistable Magnetization Switching In Multiferroic Heterostructures, T. X. Nan, Z. Y. Zhou, J. Lou, M. Liu, X. Yang, Y. Gao, S. Rand, N. X. Sun Aug 2013

Voltage Impulse Induced Bistable Magnetization Switching In Multiferroic Heterostructures, T. X. Nan, Z. Y. Zhou, J. Lou, M. Liu, X. Yang, Y. Gao, S. Rand, N. X. Sun

Nian X. Sun

We report on voltage impulse induced reversible bistable magnetization switching in FeGaB/lead zirconate titanate (PZT) multiferroic heterostructures at room temperature. This was realized through strain-mediated magnetoelectric coupling between ferroelectric PZT and ferromagnetic FeGaB layer. Two reversible and stable voltage-impulse induced mechanical strain states were obtained in the PZT by applying an electric field impulse with its amplitude smaller than the electric coercive field, which led to reversible voltage impulse induced bistable magnetization switching. These voltage impulse induced bistable magnetization switching in multiferroic heterostructures provides a promising approach to power efficient bistable magnetization switching that is crucial for information storage.


Equivalence Of Direct And Converse Magnetoelectric Coefficients In Strain-Coupled Two-Phase Systems, Jing Lou, Gerry N. Pellegrini, Ming Liu, Neil D. Mathur, Nian X. Sun Aug 2013

Equivalence Of Direct And Converse Magnetoelectric Coefficients In Strain-Coupled Two-Phase Systems, Jing Lou, Gerry N. Pellegrini, Ming Liu, Neil D. Mathur, Nian X. Sun

Nian X. Sun

We demonstrate an equivalence between direct and converse magnetoelectric effects in two-phase systems comprising piezoelectric and magnetostrictive materials. This was achieved by recasting the Maxwell relation in terms of the effective electrical and magnetic dipole moments for the system and comparing coupling strengths at the same electrical and magnetic d.c. biases. Our findings therefore apply to magnetoelectric systems comprising more than two phases and correct the two widely held but opposing views that are compromised by incorrect parameterization or inconsistent bias conditions.


Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi Aug 2013

Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi

Nian X. Sun

This paper reports on the first demonstration of an ultra-miniaturized, high frequency (215 MHz) and high sensitivity MEMS resonant magnetic field sensor based on an AlN/FeGaB bilayer nano-plate resonator capable of detecting magnetic field at nano-Tesla level. Despite of the reduced volume and the high operating frequency of the sensor, high electromechanical performances were achieved (quality factor Q ≈ 511 and electromechanical coupling coefficient kt² ≈ 1.63%). This first prototype was characterized for different magnetic field levels from 0 to 152 Oe showing a frequency sensitivity of ~ 1 Hz/nT and a limit of detection of ~ 10 nT.


Tunable Fringe Magnetic Fields Induced By Converse Magnetoelectric Coupling In A Fega/Pmn-Pt Multiferroic Heterostructure, Trifon Fitchorov, Yajie Chen, Bolin Hu, Scott M. Gillette, Anton Geiler, Carmine Vittoria, Vincent G. Harris Aug 2013

Tunable Fringe Magnetic Fields Induced By Converse Magnetoelectric Coupling In A Fega/Pmn-Pt Multiferroic Heterostructure, Trifon Fitchorov, Yajie Chen, Bolin Hu, Scott M. Gillette, Anton Geiler, Carmine Vittoria, Vincent G. Harris

Anton Geiler

The fringe magnetic field, induced by magnetoelectric coupling in a bilayer Fe-Ga/Pb(Mg1/3Nb2/3)O3_PbTiO3 (PMN-PT) multifunctional composite, was investigated. The induced external field is characterized as having a butterfly hysteresis loop when tuned by an applied electric field. A tuning coefficient of the electrically induced fringe magnetic field is derived from the piezoelectric and magnetostrictive properties of the composite. A measured maximum tuning coefficient, 4.5 Oe/(kV cm−1), is found to agree well with theoretical prediction. This work establishes a foundation in the design of transducers based on the magnetoelectric effect.


Domain Rotation Induced Strain Effect On The Magnetic And Magneto-Electric Response In Cofe2o₄/Pb(Mg,Nb)O₃-Pbtio₃ Heterostructures, Zhiguang Wang, Ravindranath Viswan, Bolin Hu, Jie-Fang Li, V. G. Harris, D. Viehland Aug 2013

Domain Rotation Induced Strain Effect On The Magnetic And Magneto-Electric Response In Cofe2o₄/Pb(Mg,Nb)O₃-Pbtio₃ Heterostructures, Zhiguang Wang, Ravindranath Viswan, Bolin Hu, Jie-Fang Li, V. G. Harris, D. Viehland

Vincent G. Harris

The present work shows good control of both magnetic and electric properties with electric and magnetic fields, respectively, for epitaxial CoFe2O4 (CFO) films on Pb(Mg,Nb)O3-PbTiO3 (PMN-PT). X-ray reciprocal space mapping revealed a transformation between a- and c-domains in the PMN-PT under electric field (E). Magnetic hysteresis loop and magnetic force microscopy (MFM) measurements showed a considerable change in the magnetic properties in specific areas of CFO layers poled by MFM probe tips. Furthermore, a pulsed electric field applied to the substrate was found to switch the magnetization of CFO between high and low values, depending on the polarity of E.


Tunable Fringe Magnetic Fields Induced By Converse Magnetoelectric Coupling In A Fega/Pmn-Pt Multiferroic Heterostructure, Trifon Fitchorov, Yajie Chen, Bolin Hu, Scott Gillette, Anton Geiler, Carmine Vittoria, Vincent Harris Aug 2013

Tunable Fringe Magnetic Fields Induced By Converse Magnetoelectric Coupling In A Fega/Pmn-Pt Multiferroic Heterostructure, Trifon Fitchorov, Yajie Chen, Bolin Hu, Scott Gillette, Anton Geiler, Carmine Vittoria, Vincent Harris

Vincent G. Harris

The fringe magnetic field, induced by magnetoelectric coupling in a bilayer Fe-Ga/Pb(Mg1/3Nb2/3)O3_PbTiO3 (PMN-PT) multifunctional composite, was investigated. The induced external field is characterized as having a butterfly hysteresis loop when tuned by an applied electric field. A tuning coefficient of the electrically induced fringe magnetic field is derived from the piezoelectric and magnetostrictive properties of the composite. A measured maximum tuning coefficient, 4.5 Oe/(kV cm−1), is found to agree well with theoretical prediction. This work establishes a foundation in the design of transducers based on the magnetoelectric effect.


Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. N. Chinnasamy, J. Y. Huang, L. H. Lewis, B. Latha, C. Vittoria, V. G. Harris Aug 2013

Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. N. Chinnasamy, J. Y. Huang, L. H. Lewis, B. Latha, C. Vittoria, V. G. Harris

Laura H. Lewis

Ferromagnetic air-stable SmCo nanoparticles have been produced directly using a one-step chemical synthesis method. X-ray diffraction studies confirmed the formation of hexagonal SmCo5 as a dominant phase. High resolution transmission electron microscopy confirms the presence of uniform, anisotropic bladelike nanoparticles approximately 10 nm in width and 100 nm in length. Values of the intrinsic coercivity and the magnetization in the as-synthesized particles are 6.1 kOe and 40 emu/g at room temperature and 8.5 kOe and 44 emu/g at 10 K, respectively. This direct synthesis process is environmentally friendly and is readily scalable to large volume synthesis to meet the needs …


A Multiband Pifa With Slotted Ground Plane For Personal Communication Handheld Devices, Naveen Kumar, Garima Saini Jun 2013

A Multiband Pifa With Slotted Ground Plane For Personal Communication Handheld Devices, Naveen Kumar, Garima Saini

Naveen Kumar

In mobile phones and several other wireless communication devices, antenna is an important element which decides the quality & performance of the device over various communication standards. In this paper, a compact internal Planar Inverted-F Antenna (PIFA) with a ground plane having two open ended slots is proposed which is very thin compared to conventional PIFA structure. By using the ground plane as a radiator element along with top plate of PIFA structure, the height of PIFA can be reduced to a great extent, which further results in reducing thickness of mobile phones. In this paper the proposed antenna has …


Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof Apr 2013

Wireless Transmission Network : A Imagine, Radhey Shyam Meena Engineer, Neeraj Kumar Garg Asst.Prof

Radhey Shyam Meena

World cannot be imagined without electrical power. Generally the power is transmitted through transmission networks. This paper describes an original idea to eradicate the hazardous usage of electrical wires which involve lot of confusion in particularly organizing them. Imagine a future in which wireless power transfer is feasible: cell phones, household robots, mp3 players, laptop computers and other portable electronic devices capable of charging themselves without ever being plugged in freeing us from that final ubiquitous power wire. This paper includes the techniques of transmitting power without using wires with an efficiency of about 95% with non-radioactivemethods. In this paper …


Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi Mar 2013

Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi

Tianxiang Nan

This paper reports on the first demonstration of an ultra-miniaturized, high frequency (215 MHz) and high sensitivity MEMS resonant magnetic field sensor based on an AlN/FeGaB bilayer nano-plate resonator capable of detecting magnetic field at nano-Tesla level. Despite of the reduced volume and the high operating frequency of the sensor, high electromechanical performances were achieved (quality factor Q ≈ 511 and electromechanical coupling coefficient kt² ≈ 1.63%). This first prototype was characterized for different magnetic field levels from 0 to 152 Oe showing a frequency sensitivity of ~ 1 Hz/nT and a limit of detection of ~ 10 nT.


Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma Mar 2013

Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er., Deepa Sharma

Radhey Shyam Meena

Grid-connected solar PV dramatically changes the load profile of an electric utility customer. The expected widespread adoption of solar generation by customers on the distribution system poses significant challenges to system operators both in transient and steady state operation, from issues including voltage swings, sudden weather-induced changes in generation, and legacy protective devices designed with one-way power flow in mind


General Formulation For The Numerical Solution Of Three-Dimensional Nonlinear Electromagnetic Field Problems, Mulukutla Sarma Feb 2013

General Formulation For The Numerical Solution Of Three-Dimensional Nonlinear Electromagnetic Field Problems, Mulukutla Sarma

Sarma Mulukutla

No abstract provided.


Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi Feb 2013

Mems Resonant Magnetic Field Sensor Based On An Aln/Fegab Bilayer Nano-Plate Resonator, Yu Hui, Tianxiang Nan, Nian Sun, Matteo Rinaldi

Matteo Rinaldi

This paper reports on the first demonstration of an ultra-miniaturized, high frequency (215 MHz) and high sensitivity MEMS resonant magnetic field sensor based on an AlN/FeGaB bilayer nano-plate resonator capable of detecting magnetic field at nano-Tesla level. Despite of the reduced volume and the high operating frequency of the sensor, high electromechanical performances were achieved (quality factor Q ≈ 511 and electromechanical coupling coefficient kt² ≈ 1.63%). This first prototype was characterized for different magnetic field levels from 0 to 152 Oe showing a frequency sensitivity of ~ 1 Hz/nT and a limit of detection of ~ 10 nT.


Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er. Jan 2013

Battery Energy Storage System In Solar Power Generation, Radhey Shyam Meena Er.

Radhey Shyam Meena

As solar photovoltaic power generation becomes more commonplace, the inherent intermittency of the solar resource poses one of the great challenges to those who would design and implement the next generation smart grid. Specifically, grid-tied solar power generation is a distributed resource whose output can change extremely rapidly, resulting in many issues for the distribution system operator with a large quantity of installed photovoltaic devices. Battery energy storage systems are increasingly being used to help integrate solar power into the grid. These systems are capable of absorbing and delivering both real and reactive power with sub-second response times. With these …


Microfabricated Nanotopological Surfaces For Study Of Adhesion-Dependent Cell Mechanosensitivity, Weiqiang Chen, Yubing Sun, Jianping Fu Jan 2013

Microfabricated Nanotopological Surfaces For Study Of Adhesion-Dependent Cell Mechanosensitivity, Weiqiang Chen, Yubing Sun, Jianping Fu

Weiqiang Chen

Cells exhibit high sensitivity and diverse responses to the intrinsic nanotopography of the extracellular matrix through their nanoscale cellular sensing machinery. A simple microfabrication method for precise control and spatial patterning of the local nanoroughness on glass surfaces by using photolithography and reactive ion etching is reported. It is demonstrated that local nanoroughness as a biophysical cue could regulate a diverse array of NIH/3T3 fi broblast behaviors, including cell morphology, adhesion, proliferation, migration, and cytoskeleton contractility. The capability to control and further predict cellular responses to nanoroughness might suggest novel methods for developing biomaterials mimicking nanotopographic structures in vivo for …