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Full-Text Articles in Engineering

Epitaxial Growth Of M-Type Ba-Hexaferrite Films On Mgo (111) || Sic (0001) With Low Ferromagnetic Resonance Linewidths, Zhaohui Chen, Aria Fan Yang, Anton Geiler, Vincent Girard Harris (1962-), C. Vittoria, Paul R. Ohodnicki, K. Y. Goh, Michael E. Mchenry, Zhuhua Cai, Trevor L. Goodrich, Katherine S. Ziemer Aug 2013

Epitaxial Growth Of M-Type Ba-Hexaferrite Films On Mgo (111) || Sic (0001) With Low Ferromagnetic Resonance Linewidths, Zhaohui Chen, Aria Fan Yang, Anton Geiler, Vincent Girard Harris (1962-), C. Vittoria, Paul R. Ohodnicki, K. Y. Goh, Michael E. Mchenry, Zhuhua Cai, Trevor L. Goodrich, Katherine S. Ziemer

Anton Geiler

Barium hexaferrite (BaM) films were deposited on 10 nm MgO (111) films on 6H silicon carbide (0001) substrates by pulsed laser deposition from a homogeneous BaFe₁₂O₁₉ target. The MgO layer, deposited by molecular beam epitaxy, alleviated lattice mismatch and interdiffusion between film and substrate. X-ray diffraction showed strong crystallographic alignment while pole figures exhibited reflections consistent with epitaxial growth. After optimized annealing, these BaM films have a perpendicular magnetic anisotropy field of 16 900 Oe, a magnetization (as 4πs) of 4.4 kG, and a ferromagnetic resonance peak-to-peak derivative linewidth at 53 GHz of 96 Oe, thus demonstrating sufficient properties for …


Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Girard Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Dae Yoon, Tomokuza Sakai, Anton Geiler, Aria Fan Yang, Yongxue He, Katherine S. Ziemer, Nian X. Sun, C. Vittoria Aug 2013

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

Anton Geiler

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.


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.


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

Anton Geiler

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

Anton Geiler

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.


Electronic Tuning Of Magnetic Permeability In Co₂Z Hexaferrite Toward High Frequency Electromagnetic Device Miniaturization, Yajie Chen, Andrew Daigle, Trifon Fitchorov, Bolin Hu, Michael Geiler, Anton Geiler, C. Vittoria, V. G. Harris Apr 2012

Electronic Tuning Of Magnetic Permeability In Co₂Z Hexaferrite Toward High Frequency Electromagnetic Device Miniaturization, Yajie Chen, Andrew Daigle, Trifon Fitchorov, Bolin Hu, Michael Geiler, Anton Geiler, C. Vittoria, V. G. Harris

Anton Geiler

The magnetic and magnetostriction properties of Z-type cobalt-doped barium hexaferrite with perpendicular c-axis crystallographic texture are presented. The hexaferrite was utilized as a component in Co₂Z/lead magnesium niobate-lead titanate multiferroic heterostructures whose tunability of permeability with electric field in terms of ferromagnetic resonance shift was supported by experiments and theoretical calculation. A permeability change of 16% was measured by an induced magnetic field of 38 Oe under the application of 6 kV/cm of electric field. These findings lay the foundation for the application of Z-type hexaferrites in tunable rf and microwave devices valued for sending, receiving, and manipulating electromagnetic signals.


Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton L. Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. G. Harris Apr 2012

Low-Loss Barium Ferrite Quasi-Single-Crystals For Microwave Application, Yajie Chen, Anton L. Geiler, Taiyang Chen, Tomokazu Sakai, C. Vittoria, V. G. Harris

Anton Geiler

Barium hexaferrites (BaFe₁₂O₁₉) are especially useful for microwave/millimeter devices. Due to large ferromagnetic resonance (FMR) loss (linewidths > 2 kOe), traditional compacts of polycrystalline Ba ferrites indeed hinder the utilization of the materials for practical devices. The present experiment demonstrates that the quasi-single-crystal Ba ferrite disks can be fabricated by a single solid-state reaction technique without liquid phase participation, combining with a processing of alignment for the ferrite seed crystals. The ferrite bulks show a pure hexagonal Ba ferrite phase, an expected 4πMs of 4.48 kG, and coercivity of 10∽20 Oe along the c axis, similar to the results of a …


Organic Chemistry: A Survival Guide For Students, Ethan C. Levine Apr 2012

Organic Chemistry: A Survival Guide For Students, Ethan C. Levine

Anton Geiler

This project reviews material from undergraduate Organic Chemistry I and II. It is meant to function as a supplement to the textbook and lecture material for the course as it is taught in universities throughout the United States. Complex ideas are broken down into simpler ones. Material is presented in conversational language, using as little scientific jargon as possible.