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Tuning Magnetic Properties of Soft Ferromagnetic Thin Films for High Frequency Applications.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Tuning Magnetic Properties of Soft Ferromagnetic Thin Films for High Frequency Applications./
Author:	Rementer, Colin Richard.
Description:	1 online resource (178 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
Contained By:	Dissertation Abstracts International79-01B(E).
Subject:	Materials science. -
Online resource:	click for full text (PQDT)
ISBN:	9780355145236

Tuning Magnetic Properties of Soft Ferromagnetic Thin Films for High Frequency Applications.
Rementer, Colin Richard.

Tuning Magnetic Properties of Soft Ferromagnetic Thin Films for High Frequency Applications. - 1 online resource (178 pages)

Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

This work focuses on the design, synthesis, characterization and integration of soft ferromagnetic multilayer structures for their applications in high frequency applications. Presently, the form factor of current telecommunication devices, i.e., antenna, is fundamentally limited by the wavelength it is designed to transmit or receive. In order to adapt to new technologies, a method for subverting this paradigm has been developed by use of magnetoelectric, strain-coupled multiferroic systems, which requires optimized ferroic materials, especially ferromagnetic thin films. Two approaches were considered to achieve this goal, doping (boron) and multilayer (NiFe) heterostructures, where FeGa was selected as the reference phase for both approaches. Doping magnetic materials with boron has been shown to enhance the magnetic softness while maintaining magnetostriction. Multilayer heterostructures offer the possibility of tuning magnetic responses by taking advantage of materials with complementary magnetic properties.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9780355145236Subjects--Topical Terms:

557839
Materials science.
Index Terms--Genre/Form:

554714
Electronic books.

Tuning Magnetic Properties of Soft Ferromagnetic Thin Films for High Frequency Applications.
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100 1 $a Rementer, Colin Richard. $3 1182971
245 1 0 $a Tuning Magnetic Properties of Soft Ferromagnetic Thin Films for High Frequency Applications.
264 0 $c 2017
300 $a 1 online resource (178 pages)
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500 $a Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
500 $a Adviser: Jane P. Chang.
502 $a Thesis (Ph.D.) $c University of California, Los Angeles $d 2017.
504 $a Includes bibliographical references
520 $a This work focuses on the design, synthesis, characterization and integration of soft ferromagnetic multilayer structures for their applications in high frequency applications. Presently, the form factor of current telecommunication devices, i.e., antenna, is fundamentally limited by the wavelength it is designed to transmit or receive. In order to adapt to new technologies, a method for subverting this paradigm has been developed by use of magnetoelectric, strain-coupled multiferroic systems, which requires optimized ferroic materials, especially ferromagnetic thin films. Two approaches were considered to achieve this goal, doping (boron) and multilayer (NiFe) heterostructures, where FeGa was selected as the reference phase for both approaches. Doping magnetic materials with boron has been shown to enhance the magnetic softness while maintaining magnetostriction. Multilayer heterostructures offer the possibility of tuning magnetic responses by taking advantage of materials with complementary magnetic properties.
520 $a Iron-gallium-boron (FeGaB) was synthesized via co-sputtering of Fe 75Ga25 and boron. The addition of boron to Fe75Ga 25 reduced the magnetocrystalline anisotropy energy, enhancing the high frequency properties. Magnetometry studies showed that the coercivity was reduced by 70% with 15% boron (at. %) while maintaining 90% of the magnetization of FeGa. Fixed frequency FMR studies showed that the addition of boron reduced the linewidth by up to 70% to a value of 210 Oe. Electrically poled hysteresis measurements showed that the film has a saturation magnetostriction of 50 microepsilon. FeGaB's properties were shown to be tunable and can be optimized by controlling the boron concentration within 11--15% but this approach did not yield the desired FMR linewidth.
520 $a Multilayers of sputtered Fe85Ga15/Ni81Fe 19, or FeGa/NiFe, were examined to tailor their magnetic softness, loss at microwave frequencies, permeability, and magnetoelasticity, leveraging the magnetic softness and low loss of NiFe, and the high saturation magnetostriction (lambdas) and magnetization (MS) of FeGa. A systematic change was observed as the number of bilayers or interfaces increases: a seven-bilayer structure results in an 88% reduction in coercivity and a 55% reduction in FMR linewidth at X-band compared to a single phase FeGa film, while maintaining a high relative permeability of 700. The magnetostriction was slightly reduced by the addition of NiFe but still maintained up to 70% that of single phase FeGa. Analyses of the domain size revealed that this effect is a function of the layer thicknesses: thinner layers have larger in-plane domains, leading to lower coercivity. The depth-dependent composition and magnetization of these heterostructures as a function of magnetic and electric fields were assessed via polarized neutron reflectometry and the rotation of magnetization of the individual layers with applied strain was found to be deterministic. The tunability of these magnetic heterostructures makes them suitable candidates for RF magnetic applications requiring strong magnetoelastic coupling and low loss.
520 $a Device functionality was assessed by integrating multilayer samples into two different antenna architectures. A surface acoustic wave (SAW) structure was used to determine the magnitude of absorption of acoustic wave energy from piezoelectric LiNbO3. Samples with the optimized 5 BL structure, 5 BL(SAW1) (50 nm) and 5 BL(SAW2) (100 nm), were fabricated and evaluated and absorbed 17 % of the acoustic energy from the strain wave. A bulk acoustic wave (BAW) structure was used to study how the material could convert the energy from an electromagnetic wave into an acoustic wave. A thick 12 BL(BAW) sample was integrated into a device and showed a low FMR linewidth and high permeability.
520 $a This work provided the proof of concept that both doping and interfacial engineering are viabl approaches for tuning the magnetic properties of FeGa, and could be extended to other magnetoelastic systems. Multilayer magnetic materials are a promising alternative to single phase ferromagnetic materials as well as doped material systems for resonator or sensor applications. The low coercivity, high permeability, and high strain sensitivity of these samples make them promising candidates for high frequency, strain-coupled multiferroic systems.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Materials science. $3 557839
655 7 $a Electronic books. $2 local $3 554714
690 $a 0794
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a University of California, Los Angeles. $b Chemical Engineering 0294. $3 1182972
773 0 $t Dissertation Abstracts International $g 79-01B(E).
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10602975 $z click for full text (PQDT)