Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 12 of 12

Full-Text Articles in Engineering

Self-Assembled Magnetic Nanowire Arrays, Ming Liu, Jalal Lagdani, Hassan Imrane, Carl Pettiford, Jing Lou, Soak Yoon, Vincent G. Harris, Carmine Vittoria, Nian X. Sun Apr 2012

Self-Assembled Magnetic Nanowire Arrays, Ming Liu, Jalal Lagdani, Hassan Imrane, Carl Pettiford, Jing Lou, Soak Yoon, Vincent G. Harris, Carmine Vittoria, Nian X. Sun

Nian X. Sun

Different self-assembled magnetic nanowire arrays were achieved with similar to 100% trapping rate on templates with nanomagnet arrays under a low external magnetic field (∽10 Oe). The principles of magnetic charge matching and dimension matching between the magnetic nanowires to be assembled and the gaps between two nanomagnets were proposed and demonstrated to be crucial for achieving low magnetostatic energy and high trapping rate. This templated self-assembly technique and the proposed template design principles have great potential for nanomanufacturing of regular arrays of magnetic nanostructures.


Soft Magnetism, Magnetostriction And Microwave Properties Of Fegab Thin Films, Jing Lou, R. E. Insignares, Zhuhua Cai, Katherine S. Ziemer, Ming Liu, Nian X. Sun Apr 2012

Soft Magnetism, Magnetostriction And Microwave Properties Of Fegab Thin Films, Jing Lou, R. E. Insignares, Zhuhua Cai, Katherine S. Ziemer, Ming Liu, Nian X. Sun

Nian X. Sun

A series of (Fe100−yGay)1−xBx (x=0–21 and y=9–17) films were deposited; their microstructure, soft magnetism, magnetostrictive behavior, and microwave properties were investigated. The addition of B changes the FeGaB films from polycrystalline to amorphous phase and leads to excellent magnetic softness with coercivity Oe, high 4πMs, self-biased ferromagnetic resonance (FMR) frequency of 1.85 GHz, narrow FMR linewidth (X band) of 16–20 Oe, and a high saturation magnetostriction constant of 70 ppm. The combination of these properties makes the FeGaB films potential candidates for tunable magnetoelectric microwave devices and other rf/microwave magnetic device applications.


Synthesis Of Ordered Arrays Of Multiferroic Nife₂O₄-Pb(Zr₀.₅₂Ti₀.₄₈)O₃ Core-Shell Nanowires, Ming Liu, Xin Li, Hassan Imrane, Yajie Chen, Trevor L. Goodrich, Zhuhua Cai, Katherine S. Ziemer, Jian Y. Huang, Nian X. Sun Apr 2012

Synthesis Of Ordered Arrays Of Multiferroic Nife₂O₄-Pb(Zr₀.₅₂Ti₀.₄₈)O₃ Core-Shell Nanowires, Ming Liu, Xin Li, Hassan Imrane, Yajie Chen, Trevor L. Goodrich, Zhuhua Cai, Katherine S. Ziemer, Jian Y. Huang, Nian X. Sun

Nian X. Sun

A synthesis method was developed for producing core-shell nanowire arrays, which involved a combination of a modified sol-gel process, electrochemical deposition, and subsequent oxidization in anodized nanoporous alumina membranes. This method was applied to generate ordered arrays of one dimensional multiferroic NiFe₂O₄ core and Pb(Zr₀.₅₂Ti₀.₄₈)O₃ (PZT) shell nanostructures. Extensive microstructural, magnetic, and ferroelectric characterizations confirmed that the regular arrays of core-shell multiferroic nanostructures were composed of a spinel NiFe₂O₄ core and perovskite PZT shell. This synthesis method can be readily extended to prepare different core-shell nanowire arrays and is expected to pave the way for one dimensional core-shell nanowire arrays.


The Effect Of Boron Addition On The Atomic Structure And Microwave Magnetic Properties Of Fegab Thin Films, Jinsheng Gao, Aria Yang, Yajie Chen, J. P. Kirkland, Jing Lou, Nian X. Sun, Carmine Vittoria, Vincent G. Harris Apr 2012

The Effect Of Boron Addition On The Atomic Structure And Microwave Magnetic Properties Of Fegab Thin Films, Jinsheng Gao, Aria Yang, Yajie Chen, J. P. Kirkland, Jing Lou, Nian X. Sun, Carmine Vittoria, Vincent G. Harris

Nian X. Sun

Varying amounts of boron were added to the host FeGa alloy to investigate its impact upon local atomic structure and magnetic and microwave properties. The impact of B upon the local atomic structure in FeGaB films was investigated by extended x-ray absorption fine structure (EXAFS) analysis. The EXAFS fitting results revealed a contraction of lattice parameters with the introduction of B. The Debye-Waller factor determined from EXAFS fitting increases as a function of boron addition and abruptly changes during the structural evolution from crystalline to amorphous that occurs near 9% B. Upon the onset of this transition the static and …


Structural And Magnetic Properties Of Ball-Milled Ni₁₁Co₁₁Fe₆₆Zr₇B₄Cu Powders, Ashish Baraskar, Yajie Chen, Soack Yoon, C. Chinnasamy, Nian Sun, Carmine Vittoria, Vincent Harris, Todd Heil, Matthew Willard Apr 2012

Structural And Magnetic Properties Of Ball-Milled Ni₁₁Co₁₁Fe₆₆Zr₇B₄Cu Powders, Ashish Baraskar, Yajie Chen, Soack Yoon, C. Chinnasamy, Nian Sun, Carmine Vittoria, Vincent Harris, Todd Heil, Matthew Willard

Nian X. Sun

Thick films of the Ni₁₁Co₁₁Fe₆₆Zr₇B₄Cu composition were synthesized via screen printing of the ball-milled ribbons of the above composition for possible use as planar inductors. The ribbons were obtained by rapid solidification. The resulting ribbon samples were annealed at 300 degrees C for 2 h to cause embrittlement. They were found to have soft magnetic properties (4πMs∽13 kG,ΔH ∽100 Oe, and Hc< 0.5 Oe). The brittle ribbons were ball milled using tungsten carbide vials and stainless steel balls in an inert atmosphere for various milling times. The sample milled for 10 h was found to have a 4πMs of about …


Electrostatic Tuning Of Ferromagnetic Resonance And Magnetoelectric Interactions In Ferrite-Piezoelectric Heterostructures Grown By Chemical Vapor Deposition, Ning Li, Ming Liu, Ziyao Zhou, Nian X. Sun, D. V. B. Murthy, Gopalan Srinivasan, Tonya M. Klein, Vladimir M. Petrov, Arunava Gupta Apr 2012

Electrostatic Tuning Of Ferromagnetic Resonance And Magnetoelectric Interactions In Ferrite-Piezoelectric Heterostructures Grown By Chemical Vapor Deposition, Ning Li, Ming Liu, Ziyao Zhou, Nian X. Sun, D. V. B. Murthy, Gopalan Srinivasan, Tonya M. Klein, Vladimir M. Petrov, Arunava Gupta

Nian X. Sun

Magnetoelectric interactions as a function of applied electric field have been studied in ferrite-ferroelectric heterostructures at microwave frequencies. The measurements are performed on 1.5–2.0 μm thick nickel ferrite (NiFe₂O₄) films grown heteroepitaxially on lead zinc niobate-lead titanate and lead magnesium niobate-lead titanate substrates using direct liquid injection chemical vapor deposition. Large shifts in the ferromagnetic resonance profile are observed in these heterostructures due to strong magnetoelectric coupling resulting from electrostatic field induced changes in the magnetic anisotropy field. Theoretical estimates of field shifts are in good agreement with the experimental data.


Spin-Spray Deposited Multiferroic Composite Ni₀.₂₃Fe₂.₇₇O₄/Pb(Zr,Ti)O₃ With Strong Interface Adhesion, Ming Liu, Ogheneyunume Obi, Jing Lou, Stephen Stoute, Jian Y. Huang, Zhuhua Cai, Katherine S. Ziemer, Nian X. Sun Apr 2012

Spin-Spray Deposited Multiferroic Composite Ni₀.₂₃Fe₂.₇₇O₄/Pb(Zr,Ti)O₃ With Strong Interface Adhesion, Ming Liu, Ogheneyunume Obi, Jing Lou, Stephen Stoute, Jian Y. Huang, Zhuhua Cai, Katherine S. Ziemer, Nian X. Sun

Nian X. Sun

Ni₀.₂₃Fe₂.₇₇O₄ (NFO)/Pb(Zr,Ti)O₃ (PZT) multiferroic composites were synthesized by spin-spray deposition of NFO film onto PZT at 90°C. Strong interface adhesion between NFO and PZT was observed, which was verified by high resolution transmission electron microscopy indicating excellent wetting between the NFO and PZT, and by the strong magnetoelectric coupling in the NFO/PZT multiferroic composite showing an electric field induced remnant magnetization change of 10%. This strong interface adhesion and low-temperature spin-spray synthesis of multiferroic materials provide an alternative route for novel integrated multiferroic materials and devices.


Electrical Tuning Of Magnetism In Fe₃O₄/Pzn–Pt Multiferroic Heterostructures Derived By Reactive Magnetron Sputtering, Ming Liu, Ogheneyunume Obi, Zhuhua Cai, Jing Lou, Guomin Yang, Katherine Ziemer, Nian Sun Apr 2012

Electrical Tuning Of Magnetism In Fe₃O₄/Pzn–Pt Multiferroic Heterostructures Derived By Reactive Magnetron Sputtering, Ming Liu, Ogheneyunume Obi, Zhuhua Cai, Jing Lou, Guomin Yang, Katherine Ziemer, Nian Sun

Nian X. Sun

Strong magnetoelectric (ME) coupling was demonstrated in Fe₃O₄/PZN–PT (lead zinc niobate–lead titanate) multiferroic heterostructures obtained through a sputter deposition process. The dependence of the magnetic anisotropy on the electric field (E-field) is theoretically predicted and experimentally observed by ferromagnetic resonance spectroscopy. A large tunable in-plane magnetic anisotropy of up to 600 Oe, and tunable out-of-plane anisotropy of up to 400 Oe were observed in the Fe₃O₄/PZN–PT multiferroic heterostructures, corresponding to a large ME coefficient of 100 Oe cm/kV in plane and 68 Oe cm/kV out of plane, which match well with predicted results. In addition, the electric field manipulation of …


Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Yoon, Tomokuza Sakai, Anton Geiler, Aria Yang, Yongxue He, Katherine Ziemer, Nian Sun, C. Vittoria Apr 2012

Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Yoon, Tomokuza Sakai, Anton Geiler, Aria Yang, Yongxue He, Katherine Ziemer, Nian Sun, C. Vittoria

Nian X. Sun

Next generation magnetic microwave devices require ferrite films to be thick (>300 μm), self-biased (high remanent magnetization), and low loss in the microwave and millimeter wave bands. Here we examine recent advances in the processing of thick Ba-hexaferrite (M-type) films using pulsed laser deposition (PLD), liquid-phase epitaxy, and screen printing. These techniques are compared and contrasted as to their suitability for microwave materials processing and industrial production. Recent advances include the PLD growth of BaM on wide-band-gap semiconductor substrates and the development of thick, self-biased, low-loss BaM films by screen printing.


Effects Of Boron Addition To The Atomic Structure And Soft Magnetic Properties Of Fecob Films, Aria Yang, Hassan Imrane, Jing Lou, Johnny Kirkland, Carmine Vittoria, Nian Sun, Vincent G. Harris Apr 2012

Effects Of Boron Addition To The Atomic Structure And Soft Magnetic Properties Of Fecob Films, Aria Yang, Hassan Imrane, Jing Lou, Johnny Kirkland, Carmine Vittoria, Nian Sun, Vincent G. Harris

Nian X. Sun

The magnetic, microwave, and the atomic structure properties of (Fe₀.₇Co₀.₃)1-xBx sputtered films on glass substrates were investigated. The addition of boron induced a decrease in coercivity and ferromagnetic resonance linewidth. The amorphous structure was formed at x ∽0.075. Extended x-ray absorption fine structure (EXAFS) of Fe and Co showed the reduced Fourier transform (FT) amplitude, and increased Debye-Waller factors as x was increased, indicating the increased disorder due to the thermal and structural displacements. Possible Fe-B bonding was observed with a reduced bond length, which indicates boron atoms' preference for staying in the interstitial sites in bcc unit cell.


Giant Magnetoelectric Coupling And E-Field Tunability In A Laminated Ni2mnga/Lead-Magnesium-Niobate-Lead Titanate Multiferroic Heterostructure, Yajie Chen, Jingmin Wang, Ming Liu, Jing Lou, Nian X. Sun, Carmine Vittoria, Vincent G. Harris Apr 2012

Giant Magnetoelectric Coupling And E-Field Tunability In A Laminated Ni2mnga/Lead-Magnesium-Niobate-Lead Titanate Multiferroic Heterostructure, Yajie Chen, Jingmin Wang, Ming Liu, Jing Lou, Nian X. Sun, Carmine Vittoria, Vincent G. Harris

Nian X. Sun

The multiferroic properties of a laminated heterostructure consisting of magnetostrictive Ni2MnGa ribbon and piezoelectric lead-magnesium-niobate-lead titanate crystal are reported. A tunability of the electric field-induced magnetic field was measured by a shift in the ferromagnetic resonance (FMR) field by 230 Oe at X-band while applying an electric field of 6 kV/cm. Concomitantly, a frequency shift in the FMR of 370 MHz was observed. The sensitive tunability stems from a large linear magnetoelectric coupling coefficient, A=41 Oe cm/kV, measured in the heterostructure. This represents a new class of metallic multiferroic heterostructures that operate at microwave frequencies.


Pulsed Laser Ablation Deposition Of Nanocrystalline Exchange-Coupled Ni₁₁Co₁₁Fe₆₇₋ₓzr₇B₄Cux (X=0,1) Films For Planar Inductor Applications, Ashish K. Baraskar, Soack Dae Yoon, Anton Geiler, Aria Yang, C. N. Chinnasamy, Yajie Chen, Nian Sun, Carmine Vittoria, Ramasis Goswami, Matthew Willard, Vincent G. Harris Apr 2012

Pulsed Laser Ablation Deposition Of Nanocrystalline Exchange-Coupled Ni₁₁Co₁₁Fe₆₇₋ₓzr₇B₄Cux (X=0,1) Films For Planar Inductor Applications, Ashish K. Baraskar, Soack Dae Yoon, Anton Geiler, Aria Yang, C. N. Chinnasamy, Yajie Chen, Nian Sun, Carmine Vittoria, Ramasis Goswami, Matthew Willard, Vincent G. Harris

Nian X. Sun

Nanocrystalline films of the Ni₁₁Co₁₁Fe₆₇₋ₓZr₇B₄Cux (x=0,1) composition were deposited on fused quartz substrates by pulsed laser deposition. For the films ofNi₁₁Co₁₁Fe₆₆Zr₇B₄Cu, the bcc grain size ranged from 5 to 8 nm in the films deposited at substrate temperatures from ambient to 300°C. Films grown at a substrate temperature of 300°C were found to have optimal magnetic properties including minima in the coercivity and ferromagnetic resonance (FMR) linewidth. The magnetic characterization studies showed coercivity Hc < 5 Oe, 4πMs ∽16 kG, and in-plane uniaxial anisotropy field (HA)∽25-30 Oe. The ferromagnetic resonance linewidth was measured to be 34 Oe and zero magnetic field …