Magnetic And Structural Characterization Of Ferrite Thin Films Grown Using Pulsed Laser Deposition

Spinel ferrite thin films have garnered special attention due to their usefulness in recent technological advances. They hold a significant promise for various device applications, including microwave devices, memory chips, transformer cores, antenna rods, and millimeter-wave integrated circuitry. These materials are attractive due to their extremely high specific resistance, high saturation magnetization, high Curie temperature, and exceptional flexibility in tailoring magnetic properties. In this dissertation, we attempt to address a most critical issue impeding the successful integration of spinel ferrites in ferrite-based microwave devices, spin-Seebeck effect (SSE)-based thermoelectric devices, and magnetostrictive device applications by presenting a successful fabrication and characterization of high-quality (Ni, Co, Fe)8́2Fe2́2O2́4 thin films with minimal defects, grown epitaxially on single crystalline lattice-matched substrates using the pulsed laser deposition method. Typically, spinel ferrite thin films such as NiFe2́2O2́4 (NFO), CoFe2́2O2́4 (CFO), and Fe2́3O2́4 (FFO), deposited by both physical vapor deposition (PVD) and chemical vapor deposition (CVD) techniques suffer from several structural defects resulting in degraded magnetic properties. These defects are primarily the formation of antiphase boundaries and misfit dislocations that result in low saturation magnetization and high magnetic saturation field. We show that by combining isostructural substrates with lower lattice-mismatch, as low as 0.06%, and optimum deposition parameters, one can successfully eliminate essentially all the film defects to obtain characteristics comparable to bulk single-crystal. We utilized spinel structured MgAl2́2O2́4, MgGa2́2O2́4, and ZnGa2́2O2́4 substrates for film growth with varying lattice mismatches with NFO, FFO, and CFO crystals. The deposited films are structurally mostly defect-free and have a smooth surface morphology with less than 200 pm root mean square (RMS) roughness. A 400 nm NFO film on ZnGa2́2O2́4 substrate shows uniaxial perpendicular anisotropy (Hu(́Æ = 0.1 (℗ł0.1) kOe), Gilbert damping parameter equal to Îł2́1ff = 9 ©7 108́21́þ (℗ł7©7108́21́æ), and very low strain-induced anisotropy (HÏ3 = 0.4 (℗ł0.1) kOe). It has also been demonstrated that similar improvements are attainable from other members of the spinel ferrite family with minimal substrate-induced film strain, such as a sharper Verwey transition in FFO films and a lower magnetoelastic uniaxial anisotropy in CFO films.

This is the Proceedings of III Advanced Ceramics and Applications conference, held in Belgrade, Serbia in 2014. It contains 25 papers on various subjects regarding preparation, characterization and application of advanced ceramic materials.

Ferrite Nanostructured Magnetic Materials: Technologies and Applications provides detailed descriptions of the physical properties of ferrite nanoparticles and thin films. Synthesis methods and their applications in numerous fields are also included. And, since characterization methods play an important role in investigating the materials’ phenomena, various characterization tools applied to ferrite materials are also discussed. To meet the requirements of next-generation characterization tools in the field of ferrite research, synchrotron radiation-based spectroscopic and imaging tools are thoroughly explored.Finally, the book discusses current and emerging applications of ferrite nanostructured materials in industry, health, catalytic and environmental fields, making this comprehensive resource suitable for researchers and practitioners in the disciplines of materials science and engineering, chemistry and physics. Reviews the fundamentals of ferrite materials, including their magnetic, electrical, dielectric and optical properties Includes discussions on the most relevant and emerging synthesis and optimization of ferrite nanostructured materials for a diverse range of morphologies Provides an overview of both the most relevant and emerging applications of ferrite magnetic materials in industry, health, energy and environmental remediation

MODERN FERRITES, Volume 1 A robust exploration of the basic principles of ferrimagnetics and their applications In Modern Ferrites Volume 1: Basic Principles, Processing and Properties, renowned researcher and educator Vincent G. Harris delivers a comprehensive overview of the basic principles and ferrimagnetic phenomena of modern ferrite materials. Volume 1 explores the fundamental properties of ferrite systems, including their structure, chemistry, and magnetism; the latest in processing methodologies; and the unique properties that result. The authors explore the processing, structure, and property relationships in ferrites as nanoparticles, thin and thick films, compacts, and crystals and how these relationships are key to realizing practical device applications laying the foundation for next generation technologies. This volume also includes: Comprehensive investigation of the historical and scientific significance of ferrites upon ancient and modern societies; Neel’s expanded theory of molecular field magnetism applied to ferrimagnetic oxides together with theoretic advances in density functional theory; Nonlinear excitations in ferrite systems and their potential for device technologies; Practical discussions of nanoparticle, thin, and thick film growth techniques; Ferrite-based electronic band-gap heterostructures and metamaterials. Perfect for RF engineers and magnetitians working in the field of RF electronics, radar, communications, and spintronics as well as other emerging technologies. Modern Ferrites will earn a place on the bookshelves of engineers and scientists interested in the ever-expanding technologies reliant upon ferrite materials and new processing methodologies. Modern Ferrites Volume 2: Emerging Technologies and Applications is also available (ISBN: 9781394156139).

Die jüngsten Fortschritte im Bereich der drahtlosen Telekommunikation und dem Internet der Dinge sorgen bei drahtlosen Systemen, beim Satellitenfernsehen und bei intelligenten Transportsystemen der 5. Generation für eine höhere Nachfrage nach dielektrischen Materialien und modernen Fertigungstechniken. Diese Materialien bieten ausgezeichnete elektrische, dielektrische und thermische Eigenschaften und verfügen über enormes Potenzial, vor allem bei der drahtlosen Kommunikation, bei flexibler Elektronik und gedruckter Elektronik. Microwave Materials and Applications erläutert die herkömmlichen Methoden zur Messung der dielektrischen Eigenschaften im Mikrowellenbereich, die verschiedenen Ansätze zur Lösung von Problemen der Materialchemie und von Kristallstrukturen, in den Bereichen Doping, Substitution und Aufbau von Verbundwerkstoffen. Besonderer Schwerpunkt liegt auf Verarbeitungstechniken, Einflüssen der Morphologie und der Anwendung von Materialien in der Mikrowellentechnik. Gleichzeitig werden viele der jüngsten Forschungserkenntnisse bei Mikrowellen-Dielektrika und -Anwendungen zusammengefasst. Die verschiedenen Kapitel untersuchen: Oxidkeramiken für dielektrische Resonatoren und Substrate, HTCC-, LTCC- und ULTCC-Bänder für Substrate, Polymer-Keramik-Verbundstoffe für Leiterplatten, Elastomer-Keramik-Verbundstoffe für flexible Elektronik, dielektrische Tinten, Materialien für die EMV-Abschirmung, Mikrowellen-Ferrite. Ein umfassender Anhang präsentiert die grundlegenden Eigenschaften von mehr als 4000 verlustarmen dielektrischen Keramiken, deren Zusammensetzung, kristalline Struktur und dielektrischen Eigenschaften für Mikrowellenanwendungen. Microwave Materials and Applications wirft einen Blick auf sämtliche Aspekte von Mikrowellenmaterialien und -anwendungen, ein nützliches Handbuch für Wissenschaftler, Unternehmen, Ingenieure und Studenten, die sich mit heutigen und neuen Anwendungen in den Bereichen drahtlose Kommunikation und Unterhaltungselektronik beschäftigen.

Proceedings of the NATO Advanced Research Workshop on Ferrimagnetic Nano-crystalline and Thin Film Magnetooptical and Microwave Materials, Sozopol, Bulgaria, 27 September - 3 October, 1998

Materials that have at least two coupled electric, magnetic, and structural order parameters resulting in simultaneous ferroelectricity, ferromagnetism, and ferroelasticity are known as multiferroic materials. Bismuth ferrite (BiFeO3) is one of the most heavily studied room temperature single-phase multiferroic material. The simultaneous existence of ferroelectricity and antiferromagnetism with cross-coupling between these order parameters has driven intense research to accomplish electric field control of magnetism. To utilize these materials in electronic applications it is desirable to increase the magnetization and magnetoelectric coupling while reducing the switching voltage and leakage current. Tuning these responses can be achieved via strain and/or elemental engineering techniques. As the former is limited by the availability of suitable high-quality substrates for control of strain state, the latter is a more flexible technique. This thesis focuses on a systematic study of growth, structural, electrical, and magnetic characterizations of epitaxial thin films of multiferroic BiFeO3 (BFO) and Fe-site substituted BiFeO3. High-quality multiferroic epitaxial films of BiFeO3 on SrRuO3 buffered(001)-oriented SrTiO3 substrates fabricated using pulsed laser deposition are investigated. Switching dynamics of BiFeO3 have been explored using three fundamental scaling laws: Kittel's law, Kay-Dunn law, and the Ishibashi-Orihara model to acquire a complete description of the dynamical behavior and its relationship to the microstructure of the films. The primary goal of this work is to explore Fe-site substitution with magnetic elements Co and Mn, and non-magnetic element Al in BFO over a wide range of compositions. The enhancement of piezoelectric properties, electrical conductivity, and magnetic properties have been achieved through cobalt substitution. On the other hand, reduction in leakage current, and enhancement in magnetic and piezoelectric properties have been achieved through Al substitution. Moreover, we analyzed the switching dynamics in the time domain and corroborated the findings with the domain structure via a microscopy technique. It is demonstrated that Fe-site substitution of BFO is indeed a viable option to achieve improved characteristics required for device use. By identifying thebenefits of Fe-site substitution, this dissertation provides a pathway to explore BFO-based alternate magnetoelectric materials with desired properties for device applications.