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Full-Text Articles in Electromagnetics and Photonics

Microwave Magnetoelectric Coupling And Ferromagnetic Resonance Frequency Tuning Of A Co₂Mnsb/Gaas/Pzn-Pt Heterostructure, Yajie Chen, Aria Yang, Moti R. Paudel, Shane Stadler, C. Vittoria, V. G. Harris Apr 2012

Microwave Magnetoelectric Coupling And Ferromagnetic Resonance Frequency Tuning Of A Co₂Mnsb/Gaas/Pzn-Pt Heterostructure, Yajie Chen, Aria Yang, Moti R. Paudel, Shane Stadler, C. Vittoria, V. G. Harris

Yajie Chen

A systematic study of electric-field-tuned ferromagnetic resonance (FMR) of a ferroelectric/ferromagnetic/semiconductor multiferroic heterostructure, consisting of a Co₂MnSb epitaxial film grown on a GaAs substrate bonded to a lead zinc niobate-lead titanate crystal, is reported. The films, grown by pulsed laser deposition, were studied for their crystallographic structure, magnetocrystalline anisotropy, and magnetostrictive and ferromagnetic resonance properties. Ferromagnetic resonance measurements were carried out at X-band frequency under the application of electric fields with external magnetic fields applied along the [110], [100], [1Ī0] and [001] directions of the Heusler film. Magnetic anisotropy fields were derived from the angular dependence of FMR measurements, yielding …


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

Yajie Chen

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 K. Baraskar, Yajie Chen, Soack Dae Yoon, C. N. Chinnasamy, Nian Sun, Carmine Vittoria, Vincent G. Harris, Todd Heil, Matthew Willard Apr 2012

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

Yajie Chen

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 …


Large Converse Magnetoelectric Coupling In Fecov/Lead Zinc Niobate-Lead Titanate Heterostructure, Yajie Chen, Jinsheng Gao, Trifon Fitchorov, Zhuhua Cai, K. S. Ziemer, Carmine Vittoria, V. G. Harris Apr 2012

Large Converse Magnetoelectric Coupling In Fecov/Lead Zinc Niobate-Lead Titanate Heterostructure, Yajie Chen, Jinsheng Gao, Trifon Fitchorov, Zhuhua Cai, K. S. Ziemer, Carmine Vittoria, V. G. Harris

Yajie Chen

Multiferroic behavior was directly verified in a laminated ferroelectric-ferromagnetic heterostructure consisting of a FeCoV thick film (70 μm) and lead zinc niobate-lead titanate (PZN-PT) single crystal. This unique heterostructure demonstrates a significant converse magnetoelectric (CME) effect corresponding to a CME coupling constant of 31 Oe/kV cm⁻¹ It derives from the soft magnetic and magnetostrictive properties (λ=60 ppm) of FeCoV alloy and the superior electromechanical properties (d32=-2800 pC/N) of PZN-PT crystal. The electric field controlled magnetic hysteresis is discussed in terms of a stress-induced anisotropy field model. The theoretical calculation is within 7% of the measured induced field of 240 Oe.


Large Tunability Of Néel Temperature By Growth-Rate-Induced Cation Inversion In Mn-Ferrite Nanoparticles, Aria Yang, C. N. Chinnasamy, J. M. Greneche, Yajie Chen, Soack D. Yoon, Kailin Hsu, C. Vittoria, V. G. Harris Apr 2012

Large Tunability Of Néel Temperature By Growth-Rate-Induced Cation Inversion In Mn-Ferrite Nanoparticles, Aria Yang, C. N. Chinnasamy, J. M. Greneche, Yajie Chen, Soack D. Yoon, Kailin Hsu, C. Vittoria, V. G. Harris

Yajie Chen

The tuning of Néel temperature by greater than 100 K in nanoparticle Mn-ferrite was demonstrated by a growth-rate-induced cation inversion. Mn-ferrite nanoparticles, having diameters from 4 to 50 nm, were synthesized via coprecipitation synthesis. The Neel temperature (TN) increased inversely to the cation inversion parameter,δ (i.e., defined as (Mn1-δFeδ)tet[MnδFe2-δ]octO₄). Concomitantly, TN increased with increased particle growth rate and particle size. These results unambiguously establish cation inversion as the dominant mechanism in modifying the superexchange leading to enhanced TN. The ability to tailor TN enables greater flexibility in applying nanoparticle ferrites in emerging technologies.


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

Yajie Chen

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

Yajie Chen

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 …


Time Domain Analyses Of The Converse Magnetoelectric Effect In A Multiferroic Metallic Glass-Relaxor Ferroelectric Heterostructure, Yajie Chen, Anton L. Geiler, Trifon Fitchorov, Carmine Vittoria, V. G. Harris Apr 2012

Time Domain Analyses Of The Converse Magnetoelectric Effect In A Multiferroic Metallic Glass-Relaxor Ferroelectric Heterostructure, Yajie Chen, Anton L. Geiler, Trifon Fitchorov, Carmine Vittoria, V. G. Harris

Yajie Chen

The dynamic time domain response of the converse magnetoelectric effect in a multiferroic Metglas®/Pb(Mg1/3Nb2/3)O₃-PbTiO₃ (PMN-PT) heterostructure, under the application of a square waveform electric field excitation of 8 kV/cm at a frequency of 0.4 Hz, is reported. The relaxation behavior followed a stretched power-law function allowing the calculation of an intrinsic time constant. Aging behavior of magnetoelectric coupling was observed after polarization switching of 1000 cycles. These phenomena are predominantly attributed to the temporal response of polarization within the PMN-PT crystal. Results elucidate the dynamic properties of relaxor-based multiferroic heterostructures and importantly define operational constraints for low frequency device operation.