Download or read book Tuning Magnetic Properties of Soft Ferromagnetic Thin Films for High Frequency Applications written by Colin Richard Rementer and published by . This book was released on 2017 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. Iron-gallium-boron (FeGaB) was synthesized via co-sputtering of Fe75Ga25 and boron. The addition of boron to Fe75Ga25 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 . 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. Multilayers of sputtered Fe85Ga15/Ni81Fe19, 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 ( s) 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. 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. 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.

Download or read book High Frequency Magnetic Properties of Ferromagnetic Thin Films and Magnetization Dynamics of Coherent Precession Project Supported by the National Basic Research Program of China Grant No 2012CB933101 the National Natural Science Foundation of China Grant Nos 11034004 and 51371093 the Program for Changjiang Scholars and Innovative Research Team in University China Grant No IRT1251 and the Specialized Research Fund for the Doctoral Program of Higher Education China Grant No 20130211130003 written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: We focus on the ferromagnetic thin films and review progress in understanding the magnetization dynamic of coherent precession, its application in seeking better high frequency magnetic properties for magnetic materials at GHz frequency, as well as new approaches to these materials' characterization. High frequency magnetic properties of magnetic materials determined by the magnetization dynamics of coherent precession are described by the Landau–Lifshitz–Gilbert equation. However, the complexity of the equation results in a lack of analytically universal information between the high frequency magnetic properties and the magnetization dynamics of coherent precession. Consequently, searching for magnetic materials with higher permeability at higher working frequency is still done case by case.

Download or read book Magnetic Properties and Applications of Ferromagnetic Thin Films with Particular Reference to Electrodeposited Layers written by Christopher David Hutchinson and published by . This book was released on 1970 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tuning the Magnetic Properties of Thin Films by Interaction with Periodic Nanostructures written by Felix Häring and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Thin Films Multilayers and Superlattices written by A. Fert and published by Elsevier. This book was released on 1991-06-06 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials Research in thin and ultrathin magnetic structures is a multidisciplinary field which heavily relies on state-of-the-art growth, characterization and theoretical approaches to build a comprehensive physical picture on how magnetic properties depend on interfacial structural issues, interlayer coupling and transport phenomena. Often in this field, the critical properties and characterization required necessitates knowledge of structural and magnetic phenomena extending over several atomic planes. Atomic controlled growth techniques are required and atomic sensitivity is needed from magnetic and structural probes. This critical knowledge is vital for device applications, providing the basis for the synergistic interactions that are predominant in this field of research. This volume is the definitive reference source for anyone interested in the latest advances and results of current experimental research in ultrathin film magnetism.

Download or read book Magnetism of Surfaces Interfaces and Nanoscale Materials written by Robert E. Camley and published by Elsevier. This book was released on 2015-10-27 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past 30 years, magnetic research has been dominated by the question of how surfaces and interfaces influence the magnetic and transport properties of nanostructures, thin films and multilayers. The research has been particularly important in the magnetic recording industry where the giant magnetoresistance effect led to a new generation of storage devices including hand-held memories such as those found in the ipod. More recently, transfer of spin angular momentum across interfaces has opened a new field for high frequency applications.This book gives a comprehensive view of research at the forefront of these fields. The frontier is expanding through dynamic exchange between theory and experiment. Contributions have been chosen to reflect this, giving the reader a unified overview of the topic. Addresses both theory and experiment that are vital for gaining an essential understanding of topics at the interface between magnetism and materials science Chapters written by experts provide great insights into complex material Discusses fundamental background material and state-of-the-art applications, serving as an indispensable guide for students and professionals at all levels of expertise Stresses interdisciplinary aspects of the field, including physics, chemistry, nanocharacterization, and materials science Combines basic materials with applications, thus widening the scope of the book and its readership

Download or read book Tuning Magnetic Order in Transition Metal Oxide Thin Films written by Alexander John Grutter and published by . This book was released on 2013 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent decades, one of the most active and promising areas of condensed matter research has been that of complex oxides. With the advent of new growth techniques such as pulsed laser deposition and molecular beam epitaxy, a wealth of new magnetic and electronic ground states have emerged in complex oxide heterostructures. The wide variety of ground states in complex oxides is well known and generally attributed to the unprecedented variety of valence, structure, and bonding available in these systems. The tunability of this already diverse playground of states and interactions is greatly multiplied in thin films and heterostructures by the addition of parameters such as substrate induced strain and interfacial electronic reconstruction. Thus, recent studies have shown emergent properties such as the stabilization of ferromagnetism in a paramagnetic system, conductivity at the interface of two insulators, and even exchange bias at the interface between a paramagnet and a ferromagnet. Despite these steps forward, there remains remarkable disagreement on the mechanisms by which these emergent phenomena are stabilized. The contributions of strain, stoichiometry, defects, intermixing, and electronic reconstruction are often very difficult to isolate in thin films and superlattices. This thesis will present model systems for isolating the effects of strain and interfacial electronic interactions on the magnetic state of complex oxides from alternative contributions. We will focus first on SrRuO3, an ideal system in which to isolate substrate induced strain effects. We explore the effects of structural distortions in the simplest case of growth on (100) oriented substrates. We find that parameters including saturated magnetic moment and Curie temperature are all highly tunable through substrate induced lattice distortions. We also report the stabilization of a nonmagnetic spin-zero configuration of Ru4 in tetragonally distorted films under tensile strain. Through growth on (110) and (111) oriented substrates we explore the effects of different distortion symmetries on SrRuO3 and demonstrate the first reported strain induced transition to a high-spin state of Ru4. Finally, we examine the effects of strain on SrRuO3 thin films and demonstrate a completely reversible universal out-of-plane magnetic easy axis on films grown on different substrate orientations. Having demonstrated the ability to tune nearly every magnetic parameter of SrRuO3 through strain, we turn to magnetic properties at interfaces. We study the emergent interfacial ferromagnetism in superlattices of the paramagnetic metal CaRuO3 and the antiferromagnetic insulator CaMnO3 and demonstrate that the interfacial ferromagnetic layer in this system is confined to a single unit cell of CaMnO3 at the interface. We discuss the remarkable oscillatory dependence of the saturated magnetic moment on the thickness of the CaMnO3 layers and explore mechanisms by which this oscillation may be stabilized. We find long range coherence of the antiferromagnetism of the CaMnO3 layers across intervening layers of paramagnetic CaRuO3. Finally, we utilize the system of LaNiO3/CaMnO3 to separate the effects of intermixing and interfacial electronic reconstruction and conclusively demonstrate intrinsic interfacial ferromagnetism at the interface between a paramagnetic metal and an antiferromagnetic insulator. We find that the emergent ferromagnetism is stabilized through interfacial double exchange and that the leakage of conduction electrons from the paramagnetic metal to the antiferromagnetic insulator is critical to establishing the ferromagnetic ground state.

Download or read book Magnetic Properties and Applications of Ferromagnetic Microwires with Amorphous and Nanocrystalline Structure written by Arcady Zhukov and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in technology involving magnetic materials require development of novel advanced magnetic materials with improved magnetic and magneto-transport properties. Additionally the tendency on miniaturisation of the modern magnetic sensors and devices stimulates development of such magnetic materials with reduced dimensionality. Certain progress has been recently achieved in fabrication of novel magnetic nano-materials (thin films, nanowires, nano-dots...), but at the same time quite sophisticated technology should be used but in many occasions the magnetic properties of these materials are rather poorer than such properties of bulk magnetic materials (amorphous ribbons, wires, sintered materials...) and the fabrication process is much more expansive and complex. On the other hand certain industrial sectors, like magnetic sensors, microelectronics, security etc, need cheap materials with reduced dimensionality but still with high magnetic properties (particularly enhanced magnetic softness). Therefore magnetic materials with outstanding magnetic characteristics and reduced dimensionality recently gained much attention. The aim of this book is to present the most relevant aspects concerning the fabrication process following by sections devoted to present significant results on the demagnetisation process, compositional dependence and processing of glass-coated mirocwires with amorphous, nanocrystalline and granular character in order to design their magnetic properties.

Download or read book Voltage Control of Magnetic Properties in Ferromagnetic Thin Films written by Jonathan Wood and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Perpendicular Magnetic Anisotropy in CoCr0 5Fe1 5O4 Ferrite Thin Films written by Ayesha Salman and published by LAP Lambert Academic Publishing. This book was released on 2015-10-13 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spinel ferrite thin films are promising candidates for high frequency applications due to their remarkable electrical and magnetic properties. Cobalt ferrite thin films have gained widespread interests in the applications of magneto-optical recording due to their large perpendicular magneto-crystalline anisotropy. The addition of non-magnetic Cr3+ ions could produce sufficient changes in the structure of cobalt ferrite. In order to achieve homogeneous cobalt chromium ferrite (CoCr0.5Fe1.7O4) thin films, various techniques such as electron beam evaporation, pulsed laser deposition (PLD), sol-gel, dip coating and spray pyrolysis have been developed. The deposition of CoCr0.5Fe1.7O4 thin films by electron beam evaporation technique is the focus of this book. This book also covers the effect of annealing temperature on structural, surface morphological, magnetic and optical properties of cobalt chromium ferrite thin films. It is noted that Ms and Hc increases with annealing temperature. Band gap energy and optical constants (n, k, ) decreases and increases with temperature indicative of good quality of thin films. So, the contents of this book will be helpful for the new researchers."

Download or read book Ferrite ferroelectric Thin Films with Tunable Electrical and Magnetic Properties written by Ranko Heindl and published by . This book was released on 2006 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: A growing need for developing new multi-functional materials operating at microwave frequencies is demanding a better understanding of ferroelectric and ferrimagnetic materials and their combinations. Some of these materials exhibit tunable physical properties, giving an extra degree of freedom in the device design. New multifunctional ferroelectric and ferrimagnetic thin film structures are investigated in this dissertation research, in which dielectric and magnetic properties can separately be tuned over a certain frequency range. The materials of choice, Ba0.5Sr0.5TiO3 (BST) and BaFe12O19 (BaM), both well studied and used in many microwave applications, were prepared using rf magnetron sputtering and pulsed laser ablation. Thin-film bilayers, multilayers and composite thin films were grown on various substrates, and their underlying microstructure and crystallographic properties were analyzed and optimized. After identifying the most successful growth conditions, dielectric and magnetic properties were measured. Unusual features in magnetic hysteresis loops in both sputtered and laser ablated films grown under different conditions were observed. Microcircuits were fabricated using optical lithography and microwave properties and tunability were tested in the range 1-65 GHz.

Download or read book Modeling Fabrication and Characterization of Magnetic Thin Films for Integrated Inductor and MRAM Applications written by Benjamin Buford and published by . This book was released on 2016 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic thin films have potential to improve devices such as on-chip inductors, and enable new technologies such as magnetic random access memory (MRAM). The use of magnetic cores in on-chip inductors is typically limited to applications well under 1 GHz. At higher frequencies, the performance of the magnetic core is severely limited by eddy current losses and ferromagnetic resonance. This work investigates the feasibility of using shape anisotropy to increase the ferromagnetic resonance frequency and thus allow the use of thin-film magnetic cores at frequencies up to 3 GHz. Magnetic cores are fabricated on top of existing chip- scale inductors. The effect of core shape and oxide layers, which are added to reduce eddy currents, on the magnetic properties of the film are investigated. Magnetic tunnel junctions (MTJs) are of interest in MRAM and spintronic logic circuit ap- plications due to their non-volatility, low-power operation, and size scalability. One limitation to the creation of scalable magnetic random access memory is thermal stability. For large devices, this energy barrier is proportional to the exchange stiffness of a material. Typically the thermal stability is measured in fabricated MRAM devices, and is used to back-calculate the exchange stiff- ness. This work presents a novel approach which uses images of magnetic domains, in conjunction with vibrating sample magnetometer and ferromagnetic resonance measurements, to measure the exchange stiffness in unpatterned films. This allows for estimation of the thermal stability that can be obtained by a given magnetic free layer without need to fabricate and measure completed de- vices. Using this approach, the exchange stiffness and expected thermal stability in MgO / CoFeB / spacer / CoFeB / MgO free layer structures with various spacer layer materials and thicknesses are compared.

Download or read book Study of Structural and Magnetic Properties of Intermetallic Thin Films written by ezhil arasan Manoharan and published by . This book was released on 2016 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intermetallic thin films have tunable magnetic properties. The magnetic phases of intermetallic thin films were tuned by changing the alloy composition of the intermetallic system. L10 Fe50Pt50 thin film has high magnetic anisotropy which makes them ideal candidates for the thin film recording media. Magnetic phases of Fe50Pt50 can be tuned by the addition of third element like Mn by forming Fe50-x Mnx Pt50 ternary alloy system. In this work magnetic phases of ordered Fe rich Fe50-xMnxPt50 and Mn rich Fe50-xMnxPt50 thin films of Fe50-x Mnx Pt50 alloy system is investigated. Fe rich Fe50-xMnxPt50 thin films are epitaxially grown on a- Al2O3 and MgO (100) substrates, while Mn rich Fe50-xMnxPt50 thin films are grown on MgO (100) substrates. The change in the magnetic properties in Fe rich Fe50-xMnxPt50 thin films due to presence of tetragonal phase and the prediction of a the presence of a new low temperature phase in the Mn rich Fe50-xMnxPt50 thin films is verified. These intermetallic films are produced in a Ultra High Vacuum sputtering system with Reflective High Energy Electron Diffraction and Auger electron spectroscopy. RHEED is used to verify epitaxy and Auger electron spectroscopy measures chemical composition.

Download or read book Prediction of the Magnetic Properties of Thin Films of Normally Ferromagnetic Materials written by Edward Joseph Kelly and published by . This book was released on 1968 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Microstructural Properties of Thin Films on Their Magnetic Properties written by Prabandha Nakarmi and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic materials are of great importance for a wide range of applications from daily usage to industrial scale equipment. Different devices require different classes of magnetic materials based on the required magnetic properties. Magnetic properties of these materials are influenced by the microstructure of the material. Therefore, a detailed understanding of the microstructures of magnetic material and their influence on the magnetic properties are extremely crucial to optimize materials for particular applications. This dissertation provides theoretical and experimental studies of the influence of the microstructural properties of ferromagnetic materials on the dynamic magnetic properties using numerical simulations and ferromagnetic resonance experiments.A theoretical investigation of the influence of the magnetic properties of multiple constituents of a material on the presence of multiple resonances observed in magnetization dynamics studies is presented in the second chapter of this dissertation. In addition, this chapter also provides insights regarding the consequences of erroneous model assumptions on extraction of material parameters from studies of the magnetization dynamics. The understanding gained from the studies of the second chapter is used in chapter three to study the presence of two strong resonances in cobalt-based nanocomposites and its derivatives synthesized by addition of cobalt and boron. Furthermore, detailed structural and magnetic analyses of cobalt and boron added nanocomposites under the influence of annealing are presented in the third chapter of this dissertation. In chapter four, the influence of defects on the Gilbert damping in polycrystalline iron is investigated. Detailed ferromagnetic resonance studies of the polycrystalline iron samples showed a surprising insensitivity of the damping parameter to defects present in the samples at room temperature.

Download or read book Investigation of Magnetic Relaxation Mechanisms and Dynamic Magnetic Properties in Thin Films Using Ferromagnetic Resonance fmr Technique written by Behrouz Khodadadi and published by . This book was released on 2016 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigating the damping processes and the behavior of dynamic magnetic properties in ferromagnetic thin films has been an important key towards design and fabrication of different microwave and magnetic recording devices. This thesis discusses the dynamic magnetic properties and also the physics behind different relaxation mechanisms in ferromagnetic thin films using comprehensive experimental investigations by means of broadband ferromagnetic resonance (FMR) technique. In chapter one the basics of ferromagnetic resonance technique and the experimental features of the FMR setup used in this study are discussed, also the FMR data analysis is explained. Chapter two is devoted to the study of the interfacial perpendicular magnetic anisotropy (PMA) and damping parameter in Co2FeAl thin films. In chapter three broadband temperature dependent FMR measurements were carried out on Ni80Fe20/Gd thin films to investigate the behavior of ferromagnetic relaxation, and gyromagnetic ratio as the system goes through the Curie temperature of Gd. In chapter four, the ferromagnetic relaxation mechanisms in ferrites are discussed. The low loss Nikel Ferrite and Lithium ferrite single crystal, thin and ultra-thin films were characterized by detailed FMR measurements to investigate the effect of microstructural defects on the magnetization relaxation. A comprehensive study on the interlayer exchange coupling strength in Co90Fe10/Ru/ Co90Fe10 multilayers is the subject of chapter five, in which the mutual spin pumping is discussed as a recently discovered channel for relaxation in exchange coupled multilayers.

Download or read book Metallic Films for Electronic Optical and Magnetic Applications written by Katayun Barmak and published by Woodhead Publishing. This book was released on 2014-02-13 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallic films play an important role in modern technologies such as integrated circuits, information storage, displays, sensors, and coatings. Metallic Films for Electronic, Optical and Magnetic Applications reviews the structure, processing and properties of metallic films. Part one explores the structure of metallic films using characterization methods such as x-ray diffraction and transmission electron microscopy. This part also encompasses the processing of metallic films, including structure formation during deposition and post-deposition reactions and phase transformations. Chapters in part two focus on the properties of metallic films, including mechanical, electrical, magnetic, optical, and thermal properties. Metallic Films for Electronic, Optical and Magnetic Applications is a technical resource for electronics components manufacturers, scientists, and engineers working in the semiconductor industry, product developers of sensors, displays, and other optoelectronic devices, and academics working in the field. Explores the structure of metallic films using characterization methods such as x-ray diffraction and transmission electron microscopy Discusses processing of metallic films, including structure formation during deposition and post-deposition reactions and phase transformations Focuses on the properties of metallic films, including mechanical, electrical, magnetic, optical, and thermal properties