MS, University of Cincinnati, 2004, Engineering : Mechanical Engineering

Friction has been a complicated subject to understand for many years. Much can be attributed to the complex, non-linear nature of friction and its implicit influence on the system parameters. Besides research pointed at understanding the fundamental principles and characters of friction, the interaction of friction dynamics and system dynamics has been a study of much interest. This work covers the interaction of friction and system dynamics. Two different models involving dry friction, distinguished by the number of DOF have been studied: - Single-DOF model with external excitation (Den Hartog's model) - Two-DOF model with external excitation (Extension of Pratt & William's model). The first model is studied to understand the general response characteristics like stick-slipbecause of friction and external forces. The latter part of this work is an extension to the second model. The results obtained have been validated with earlier works to show more confidence in the observations made thereafter. The difference in the system parameters on the masses brings asymmetry in the system. This is studied in the joint problem. Two resonant peaks are observed in the FRF plot for an unsymmetrical system; the resonant frequency peaks shift farther from each other with increasing unsymmetry in the system. Also, the influences of normal load and excitation frequency on the percentage stick, energy dissipation and frequency shifts are studied. Better understanding of the joint dynamics with friction interfaces provides necessary insight into the uses and effects of friction damping so as to increase the energy dissipation and minimize unwanted response.

Committee: Dr. Edward Berger (Advisor) Subjects:

Master of Science, Miami University, 2023, Physics

We infer the damping coefficient of cold atoms in a magneto-optical trap by capturing images of the expanding atomic cloud in optical molasses, followed by a measurement of the diffusion constant and temperature. In order to verify our inferred value obtained for the damping coefficient, we attempt to measure the damping coefficient using an alternative experiment. By introducing a perturbing force from an applied bias magnetic field, that shifts the atom cloud's center of mass. A measurement of the characteristic time taken by the cloud to spatially relax back to its equilibrium position permits us to deduce the damping coefficient. However, eddy currents resulting from the rapid switching of the bias magnetic field prevented us from making accurate measurements of the damping coefficient.

Committee: Samir Bali Dr (Advisor) Subjects: Physics

Doctor of Philosophy, University of Akron, 2021, Electrical Engineering

Acoustic noise and vibration prediction, mitigation, and performance optimization, in electric machines, are studied in this dissertation. First, vibration prediction enhancement in electric machines through frequency-dependent damping characterization is proposed in this dissertation. Different methods of mass and stiffness-dependent Rayleigh damping coefficient calculation are studied to identify the best damping estimation strategy. The proposed damping estimation strategy is used to predict the vibration spectrums of two 12-slot 10-pole (12s10p) permanent magnet synchronous machine (PMSM) designs and predicted vibration spectrums are experimentally validated through run-up tests of two prototypes. Moreover, to eliminate the dependency of the damping estimation strategy on the availability of a prototype, a damping coefficient prediction methodology is proposed. The proposed prediction methodology is experimentally validated using a third 12s10p PMSM prototype. Secondly, a lumped unit response-based sensitivity analysis procedure is introduced, which isolates electromagnetic and structural impacts brought by variation of different design parameters in an electric machine. The lumped unit response strategy utilizes the frequency-dependent damping estimation method developed early in the dissertation. The impact of different generic design parameters and a structural feature on a range of output quantities are studied in detail for a 12s10p PMSM. Analysis reveals that on a 12s10p PMSM, slot opening has a very high impact on the dominant airgap force component. A multi-level non-linear regression model-based optimization strategy is introduced considering electromagnetic and structural design objectives and constraints following the sensitivity analysis. A 12s10p PMSM prototype is tested to validate the FEA simulations used during the optimization process. Finally, the lumped unit response-based vibration prediction methodology devel (open full item for complete abstract)

Committee: Dr. Yilmaz Sozer (Advisor); Dr. Malik E. Elbuluk (Committee Member); Dr. J. Alexis De Abreu Garcia (Committee Member); Dr. D. Dane Quinn (Committee Member); Dr. Kevin Kreider (Committee Member) Subjects: Automotive Engineering; Electrical Engineering; Electromagnetics; Electromagnetism; Engineering; Mechanical Engineering; Technology

PhD, University of Cincinnati, 2020, Engineering and Applied Science: Mechanical Engineering

A two-step approach is developed to build an FEM model of a clamped structure focusing on the boundary stiffness and damping definitions. The approach utilizes FE model correlation with experimentally obtained modal parameter estimates to calibrate the model. Model calibration is first carried out in a free-free state to update the geometry, mass and material properties of the structure. The calibrated free-free model is then updated in two stages to include the boundary stiffness and damping for a clamped state. Stiffness is addressed first followed by damping. The stiffness is defined in terms of contact stiffness definitions in terms of normal and tangential stiffness at the boundary. Contact stiffness is determined by matching analytical and measured natural frequencies of the clamped built-up structure. Calibration is carried out in a mode-wise manner and the system response is calculated in the frequency domain in bands centered around each mode of interest. In the second step, the damping property of the structure is identified based on responses at resonance. The significance of spatial distribution of damping is studied by first developing an approach to include accurate spatial distribution in models based on intuitive knowledge of the location of damping and then using it to compare against models built with traditional damping models such as Rayleigh and modal damping. Accurate representation of spatial distribution of damping in FE models was observed to be not very important for lightly damped structures. The stiffness and damping modeling approaches developed were combined and demonstrated on a clamped steel beam. The calibrated model is then validated by demonstrating its ability to make accurate strain predictions to arbitrary load cases. Random broadband and banded chirp loads were both used to compare the system responses from simulation and testing. Simulated FRF from calibrated system and the force spectra of interest are used to obtain th (open full item for complete abstract)

Committee: Jay Kim Ph.D. (Committee Chair); Randall Allemang Ph.D. (Committee Member); Allyn Phillips Ph.D. (Committee Member); Yongfeng Xu Ph.D. (Committee Member) Subjects: Mechanical Engineering

Master of Science in Engineering, University of Akron, 2018, Mechanical Engineering

Nanostructured materials with superior physical properties hold promise for the development of novel nanodevices. Full potential applications of such advanced materials require study of vibrational analysis to reduce equipment downtime and maintenance cost of the unit by detecting the experimental faults when applied in industries, in general, it is a study concerning the system under oscillatory motion about a stable equilibrium position focusing on the analysis not the design of the systems. Which in turn necessitates the development of computer-based simulations along with novel experimental techniques. Since controlled experiments are difficult for nanoscale materials and atomic studies are computationally expensive, continuum mechanics-based simulations of nanomaterials and nanostructures have become the focal points of computational nanoscience and materials modeling. In this thesis, the free and forced vibrations of coupled coaxial carbon nanotube in the vicinity of graphene sheet using Euler Bernoulli beam model for free-free end conditions are studied. The multiwalled carbon nanotube can be studied by considering each of the nested nanotubes to be a Euler Bernoulli beam and coupled through the Van der Waals forces. Damping is also considered and modeled using a Kelvin-Voigt damping model. Using the estimated Van der Waals interaction energy potential using Lennard-Jones potential expressed as a function of interlayer spacing. Equilibrium distance affects the natural frequencies of the system and is calculated in the thesis. To study the forced response of coupled co-axial nanotube with damping a modal analysis is performed assuming graphene has a harmonic excitation. There is a necessity to develop a solution method to determine the response of a system for all times and even after the excitation is removed. Many excitations change form at the discrete time, so it is convenient to determine a unified mathematical form of response. In this Thesis, the solu (open full item for complete abstract)

Committee: Graham Kelly Dr. (Advisor); Alper Buldum Dr. (Committee Member) Subjects: Automotive Materials; Chemistry; Design; Engineering; Mechanical Engineering; Mechanics; Molecular Chemistry; Nanoscience; Nanotechnology

PhD, University of Cincinnati, 2006, Engineering : Mechanical Engineering

Damping matrices have been formulated based on a simple model such as the proportional or structural damping when building a numerical model of a dynamic system. Such simple models, which were proposed largely for mathematical convenience, match only the overall effect of damping but ignore the actual mechanism or spatial distribution of damping. Motivated by the desire to obtain a more accurate damping matrix, various approaches have been proposed, which typically utilize some form of experiment. Among these methods, the dynamic stiffness matrix (DSM) based damping identification method is attractive because of its simplicity and generality. However, the damping matrices identified by the method were found to have unexpected forms, and also be heavily contaminated by experimental errors. Through numerical simulations and experimental work, the sources of experimental errors are identified and studied in this work. Based on the understanding obtained from the study, an improved experimental procedure is developed to minimize the errors involved in the DSM method. The test procedure is applied to two simple experimental cases to demonstrate the feasibility of the DSM based damping identification method. The development of the DSM based damping matrix identification method was motivated by the desire to apply it to building an experimental-analytical hybrid model by combining the damping matrix expanded from the experimentally identified damping matrix with analytically formulated stiffness and mass matrices. To enable this, two methods are developed to expand the experimental damping matrix to the size of the analytical model. A simple but effective method is developed to find the frequency range in which the matrix expansion is valid. As another important application of the DSM based damping identification method, the method is applied to the measurement of the property of viscoelastic materials. It is shown that how the method can be utilized to identify the struct (open full item for complete abstract)

Committee: Dr. Jay Kim (Advisor) Subjects: Engineering, Mechanical

MS, University of Cincinnati, 2002, Engineering : Mechanical Engineering

Modeling of distributed damping characteristics are increasingly important for validating analytical structural models and correlating experimental and analytical data. In addition, damping mechanisms are a measure of structural conditions since they are sensitive to small structural changes. Thus, identification of localized changes in damping has uses in the field of damage identification. A new method to experimentally identify spatial damping, which was developed by Lee and Kim, has been studied in this research. The method fits matrix coefficient polynomials to the real and imaginary parts of the dynamic stiffness matrix (DSM, the inverse of the frequency response matrix). The real DSM coefficients represent dynamically conservative features of the system, namely mass and stiffness. The imaginary DSM coefficients model the dynamic energy removal mechanisms of the structure, namely damping. The greatest strength of the method is its simplicity and computational efficiency. Once data is collected experimentally, only two steps are required: a FRF matrix inversion (frequency line by line), and a polynomial fit for the real and imaginary components of the DSM. Since both DSM components are fit independently, the damping properties of a system may be identified without any prior knowledge about the system's mass and stiffness. Likewise, the damping calculation is not subject to errors in any pre-determined structural values. The work is broken up into three segments. First, the DSM algorithm is derived and features of the algorithm are discussed. Next, the DSM algorithm is applied to several analytical systems and several qualitative and quantitative validation tools are presented. Finally, the DSM algorithm and validation tools are applied to three experimental case studies. Practical issues are discussed and benefits and limitations of the algorithm are observed.

Committee: Dr. David Brown (Advisor) Subjects: Engineering, Mechanical

Master of Science, Miami University, 2007, Physics

The usual magnetorheological (MR) fluid dampers get energy externally to effectively damp unwanted motion. Recent research focuses on self-powered systems that get their energy internally from the vibrations. We have characterized the electromagnetic induction (E.M.I.) damper by two methods. First, a magnet freely traverses a coil of wire like in an Atwood machine and secondly, a magnet is driven sinusoidally in a coil of wire placed on a force sensor. In the first method, we look into how best to model the conversion of mechanical energy into electrical energy. Secondly, damping force is measured in relation to induced voltage and linear velocity. Coefficient of damping of different coils is measured and compared with different wire thickness and magnet length to coil width ratio. An E.M.I damping model is introduced and used in both cases to explain the phenomena of E.M.I. damping.

Committee: Michael Pechan (Advisor) Subjects:

Master of Science, The Ohio State University, 2013, Mechanical Engineering

An experiment is designed to measure the vibro-acoustic effects of minimal constrained layer damping patches applied to a thin cylindrical shell. A patch placement procedure developed for rectangular plates is adapted for the cylindrical shell application. The procedure proposes placing damping patches on the structural anti-nodes of the vibrating structure for significant noise and vibration reduction. First, impact testing is performed to determine the first 11 non-zero natural frequencies and mode shapes of the shell. Next, vibration and acoustic responses are measured under harmonic excitation of the shell using an electrodynamic shaker. These responses are measured for the untreated shell as well as multiple damping patch treatment configurations. The results verify the ability to treat certain modes as specified by the adapted procedure. Over the frequency range from 200 to 1500 Hz, reductions in vibration response of 2-8 dB and in radiated noise of 3-11 dB are measured with patches covering only two percent of the shell surface area. Finite element and boundary element models are developed to computationally predict changes in radiation efficiency. System damping measured from vibration testing is applied to the computational model to simulate the effects on radiated noise due to the additional damping introduced by the patches. The integrated structural-acoustic computational model shows a trend of radiated noise reduction as system damping increases; however, the predicted radiated noise reduction exhibits a large spread and does not seem to follow a one-to-one correlation with the reduction in damping. These results suggest additional complexities in the modal radiation efficiencies and assumed damping values are present, which should be addressed in future studies.

Committee: Rajendra Singh (Advisor); Jason T. Dreyer (Committee Member); Brian Harper (Committee Member) Subjects: Mechanical Engineering

Master of Science, The Ohio State University, 1967, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, The Ohio State University, 2023, Physics

This thesis describes the role of magnetic materials in modern information technology research and application. Meanwhile, hybrid quantum systems are gaining great attention in the quantum computing area, which studies and manipulates the coupling physics between different platforms. Yttrium iron garnet (YIG) is one of the lowest magnetic damping materials and long has been studied for its potential in magnon-based information transmission, processing and storage. The integration of low damping YIG thin film in hybrid quantum systems is a promising research direction but has been hindered by its strongly increased damping due to its interaction with the gadolinium gallium garnet substrate, which YIG is commonly deposited on. In this thesis' work, improvement can be made by using a diamagnetic buffer layer or diamagnetic substrate, and a damping constant even lower than room temperature is obtained. Strong coupling in a hybrid system that incorporates a superconducting microwave resonator and the YIG film was demonstrated and proves that YIG epitaxial thin film can be an attractive candidate in low temperature applications.

Committee: Fengyuan Yang (Advisor); Richard Hughes (Committee Member); Jay Gupta (Committee Member); Nandini Trivedi (Committee Member) Subjects: Physics

Master of Science in Mechanical Engineering (MSME), Wright State University, 2023, Mechanical Engineering

The focus of this study was to select triply periodic minimal surface (TPMS) structures made of 3D-printed polymers. The primary variables in this study were: TPMS shape, lattice volume ratio, and lattice material. Vibration absorption was characterized by damping ratio via transmissibility at the system's natural frequency. The vibration testing was performed using an electro-dynamic shaker, a known mass, an input/control accelerometer, and an output/response accelerometer. The 3D-printed absorber/lattice was mounted to the shaker baseplate and a mass will be mounted on top of the absorber. One accelerometer will be mounted to the shaker baseplate and the other will be mounted to the top of the mass. A broadband frequency sweep was the test type for the vibration absorption characterization in this study. Additional testing was performed to help further characterize other properties of the lattice structure. Monotonic load testing was performed to calculate the stiffness of the lattice. This information was used to determine a suitable mass to use for vibration testing. The results show a clear separation in the damping performance of PLA vs TPU, with TPU having the better performance.

Committee: Ahsan Mian Ph.D. (Advisor); Sheng Li Ph.D. (Committee Member); Raghavan Srinivasan Ph.D., P.E. (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy (Ph.D.), University of Dayton, 2022, Mechanical Engineering

Because of the high cost and time-consuming foundation work, structural modifications for seismic rehabilitation and wind-induced vibration mitigation may not be appropriate for all buildings. Auxiliary damping has gained popularity in recent years, especially in structures such as mid- and high-rise buildings. Distributed damping systems (typically viscous and viscoelastic) or reactive damping systems are the two types of damping systems for such structures (typically tuned mass dampers). In this study analytical and numerical tools for modeling and design of multilayer viscoelastic damping devices, to be used in dampening the vibration of large structures, are developed. Considering the limitations of analytical models for synthesis and analysis of realistic, large, multi-layer VE dampers, the emphasis of the study has been on the numerical modeling using finite element analysis. To verify the finite element models, a two-layer VE damper was built, tested, and the measured parameters were compared with the numerically predicted ones. The numerical model prediction and experimentally evaluated damping and stiffness of the test VE damper were in very good agreement. To demonstrate the effectiveness of VE dampers in adding auxiliary damping to larger structures, one such damper is designed and incorporated numerically into the model of a frame subject to wind loading. Comparison of the response of the frame to the aforementioned load, without and with the VE damper clearly shows the efficacy of the damper in lowering the extent of motion. Distributed VE dampers are normally configured as braces or damping panels which are engaged through relative small movements between the structural members when the structure sways under wind or earthquake loading. In addition to being used as stand-alone dampers in distributed damping applications, VE dampers can also be incorporated into the suspension element of tuned mass dampers (TMDs). Tuned mass dampers on the ot (open full item for complete abstract)

Committee: Reza Kashani (Advisor); David Myszka (Committee Member); Elias Toubia (Committee Member); Youssef Raffoul (Committee Member) Subjects: Civil Engineering; Mechanical Engineering

MS, University of Cincinnati, 2021, Medicine: Biostatistics (Environmental Health)

Bone damping is a non-invasive measure of bone fragility and is identified as a better predictor of osteoporosis (OP) related bone fracture/fragility than bone mineral density (BMD). Subject with higher damping value demonstrates a heightened resistance to fracture. The purpose of this study was to identify the predictors of bone shock absorption (BSA) capacity measured as a damping factor by using model selection and multivariate multiple regression (MMR) method as well as regression tree. The main dataset was from an existing Cincinnati Lead Study (CLS) cohort. It is a prospective and longitudinal study examined early and late effects of childhood lead exposure on growth and development. The results of this study indicated that cortical vBMD, cortical thickness, endosteal circumference, cortical section modulus, current weight, and the number of pregnancies carried until the 3rd trimester were significant predictors of bone damping factor based on the method of model selection and MMR. Among the predictors with top nine highest variable importance values in regression tree method, four are the same as significant predictors from MMR analysis. Those are current weight, cortical section modulus, cortical vBMD, and endosteal circumference. Cortical section modulus and cortical vBMD have positive relationship with damping factor; however weight and endosteal circumference have negative relationship with damping factor. All variables' relationships with damping factor are clinically significant. Lack of dataset from normal people to compare the differences and the missingness of the data are the limitation of the study. Current weight, cortical section modulus, cortical vBMD, and endosteal circumference are significant predictor of damping factor based on the study results. They are biologically relevant to damping and statistically significant in the damping model.

Committee: Amit Bhattacharya (Committee Member); Marepalli Rao Ph.D. (Committee Chair) Subjects: Biostatistics

Master of Science in Polymer Engineering, University of Akron, 2021, Polymer Science

Torsional shape memory property of spider Major Ampullate (MA) silk is a fascinating, yet less well-established property in spider's behavioral ecology. A MA silk that first oscillates near the twist angle and form a new equilibrium, over a long period of time, followed by returning to the starting twist angle without using any other external factors is defined as torsional shape memory. Because the mechanical properties of MA spider silk are a strong function of humidity (change in diameter and length in humidity; supercontraction), our hypothesis is that the torsional shape memory for the MA silk will depend on humidity. Here, MA silk of Larinoides cornutus was twisted in different strain twist angles and different humidity using a magnetic field and allowed for free oscillation. We found that the MA silk of Larinoides cornutus does not exhibit shape memory properties for small twists angles (30˚ and 90˚) for humidity at 30%, 60% and 90%, which is different from the published result of Araneus diadematus. For a large twist angle of 270˚, the MA silk undergoes plastic deformation for all values of humidity studied here. This study provides the evidence of how humidity and twist angle affect the torsional modulus of MA silk of Larinoides cornutus.

Committee: Tianbo Liu (Committee Member); Ali Dhinojwala (Advisor); Nita Sahai (Committee Member) Subjects: Biophysics; Polymers

Master of Science, The Ohio State University, 2021, Mechanical Engineering

To facilitate experimentation in the field of gas turbine disk dynamics, a new integrally bladed disk, or blisk, was designed and manufactured for use at The Ohio State University (OSU) Gas Turbine Laboratory. The axisymmetric disk portion of the equipment and the blades are manufactured as a single unit in blisks. This new blisk is referred to hereafter as the OSU Rotor 67 Blisk. The OSU Rotor 67 Blisk was designed with traditional airworthy gas turbine rotating hardware standards in mind, although it is not meant for flight. The standards put forth by the Federal Aviation Administration (FAA) are loosely followed to produce a blisk that is similar to hardware that could be used in general aviation. The guidelines put forth by the FAA for rotor design are found in 14 CFR Part 33, and provide requirements for safety aspects of rotor design. The airfoil design and mounting configuration were strongly influenced by the existing NASA Rotor 67 airfoil and disk geometry, with modifications to convert it from a bladed disk to a blisk. Additionally, damper grooves were added to the design to facilitate a variety of damping experiments. After the OSU Rotor 67 Blisk was machined, balanced, and inspected, it was received at OSU, where it was subsequently tested on a non-rotating bench setup to characterize its properties. A roving modal hammer was used along with a calibrated capacitance probe for dynamics measurements. The data generated through the dynamics experiments provided clarity on the natural frequencies and the mistuning of the blisk. These data will be used to design future experiments at the OSU Gas Turbine Laboratory where the blisk will be rotated at different operating speeds and excited by air-jets to evaluate different damping technologies.

Committee: Kiran D'Souza (Advisor); Michael Dunn (Advisor); Randall Mathison (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2021, Mechanical Engineering

Turbomachinery, like jet engines and industrial gas turbines in power plants, are very advanced and complex machines. Due to the complexity and cost of modern turbomachinery, there is active research in accurately predicting the physical system dynamics using computational models. Two big mechanisms that affect the structural response are the prestress effects from high rotational speeds and mistuning effects from tolerance deviations, wear, or damage. Understanding the role these two mechanisms play in the computational modeling of these systems is an important step toward a complete digital twin of an entire jet engine. There previously existed modeling methods that enabled each to be analyzed independently, but not simultaneously in an efficient manner. This will be one of the focus points of this dissertation. The other focus being an experimental investigation into exciting system resonances of a rotating bladed disk using air jets. These experiments will be used to validate the computational modeling method developed. This dissertation has three primary objectives. The first objective is to present reduced order modeling methods that allow for the efficient modeling of coupled systems and rotating systems, both with small or large mistuning. By efficiently including these mechanisms, more realistic boundary conditions can be used to help validate the reduced order models (ROMs) with experimental data. Both modeling methods create models a fraction of the size of the full model while retaining key dynamic characteristics of the full model. The second objective of this work is to show the capability of air jets in exciting synchronous and non-synchronous vibrations in a rotating bladed disk. Much previous research in this field focused on experiments with stationary systems. These tests can help isolate specific mechanisms that may be present in bladed disks, but may limit the applicability of the results to actual rotating systems. This work presents a method (open full item for complete abstract)

Committee: Kiran D'Souza (Advisor); Randall Mathison (Committee Member); Manoj Srinivasan (Committee Member); Herman Shen (Committee Member) Subjects: Mechanical Engineering

Master of Science, Miami University, 2020, Mechanical and Manufacturing Engineering

Vibration based monitoring techniques are widely used to detect damage, monitor the growth of inherent defects, system identification, and material parameter estimation for various engineering applications. These techniques present a non-invasive and relatively inexpensive tool for various biomedical applications, for example, in characterizing the mechanical properties of the bone and muscles of humans as well as animals. In recent years, it has been shown that fundamental natural frequencies and corresponding damping ratios can be correlated to the bone health quality indicators as associated with osteoporosis, osteoarthritis etc. In this research, through the investigation of clinical data, an analysis procedure is developed to investigate the correlation between the damping properties associated with both lower and higher modes of vibration and bone health quality. Subsequently, a data-driven system identification tool for reconstructing the parameters (mass, stiffness, damping distributions) in a low-dimensional human model is developed which utilizes selected measurements from the clinical study. It is anticipated that the analysis process and parameter identification techniques presented here can be developed and tuned for any individual human model and can be can be used as osteological monitoring tool for predicting early diagnostics pre-cursors of the bone or muscle related conditions or diseases.

Committee: Kumar Singh (Advisor); James Chagdes (Committee Member); Mark Walsh (Committee Member) Subjects: Biomechanics; Biomedical Engineering; Mechanical Engineering; Osteopathic Medicine

Doctor of Philosophy, The Ohio State University, 2020, Physics

Magnetic data storage has proven to be a viable technique to hold non-volatile memory in which the direction of magnetization is utilized to represent the 0 or 1 state of a computer bit. While various forms of magnetic data storage have been implemented in devices for decades, recent advances in thin film deposition and magnetic characterization techniques have shed light on new approaches to engineering advantageous magnetic properties in novel magnetic materials that can improve their performance. The work reported in this dissertation demonstrates the ability to produce and tune several magnetic properties in two types of material systems that are incorporated into thin film heterostructures. The first system is insulating rare earth garnets, where the first measurement of topological magnetic textures in an insulator at room temperature is reported as well as the detection of a novel and significant interfacial anisotropy due to non-magnetic capping layers. The second system is CoxFe1-x, where the magnetic damping is reduced to the lowest value ever reported for a metallic ferromagnet and the perpendicular magnetic anisotropy is significantly enhanced. All of these material properties and magnetic interactions are improved through epitaxial growth on various substrates. These results highlight the unique properties exhibited by these two material systems, which are beneficial for their potential integration into future spintronic applications.

Committee: Fengyuan Yang (Advisor); Jay Gupta (Committee Member); Andrew Heckler (Committee Member); Ralf Bundschuh (Committee Member) Subjects: Physics