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Articles 31 - 60 of 369

Full-Text Articles in Condensed Matter Physics

Low Energy Ion Irradiation Effects In Electronic Devices And Materials, David C. Mccall Aug 2025

Low Energy Ion Irradiation Effects In Electronic Devices And Materials, David C. Mccall

All Dissertations

The physics and engineering of ion-solid interactions are governed by the ion beam characteristics (flux, charge, energy) and target(s) in question. Here I present work on two projects related to the extraction of a high flux of low charge state Argon ions from a commercial plasma source and the irradiation of an engineered target, a transistor, with high charge state Argon ions.

An end-Hall ion source that produces a a high current plasma of ions and electrons in a rough vacuum environment is characterized. Using a Langmuir probe and multiple pressure measurements, the ion and electron content of the source …


Ferroelectricity And Multiferroicity In Ultrathin Films Of Unconventional Transition Metal Oxide, Xin Li Aug 2025

Ferroelectricity And Multiferroicity In Ultrathin Films Of Unconventional Transition Metal Oxide, Xin Li

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Ferroic orders of transition metal oxides, such as ferroelectricity and ferromagnetism, are determined by the intercoupling between spin, charge, lattice. Consequently, ferroic epitaxial thin films have attracted wide interest due to the profuse novel phenomena and the great application potentials for modern electronics. However, the mainstream of the study for transition metal oxides has focused on perovskite structure, limiting the understanding and discovery of novel phenomena associate with ferroic orders. In this thesis, the epitaxial films of hexagonal rare-earth ferrites (h-RFeO3) and fluorite-structure hafnia oxide (HfO2) are studied comprehensively, providing new experimental and theoretic …


Advancing Lithium-Ion Batteries Through Exploration Of Novel Physico-Chemical Phenomena, Peshal Karki Aug 2025

Advancing Lithium-Ion Batteries Through Exploration Of Novel Physico-Chemical Phenomena, Peshal Karki

All Dissertations

Lithium-ion batteries (LIBs) power a wide range of modern devices, from smartphones to electric vehicles. This dissertation integrates materials characterization and electrochemical testing to develop novel Si-based electrode materials, investigate separator effects, and improve electrochemical impedance spectroscopy (EIS) modeling. First, I synthesized Si@CC composites using bio-based carbon sources and discovered a novel in situ disorder reduction in the amorphous carbon cloud during cycling, attributed to Si volume fluctuations and mesoporous carbon structure, which enhanced capacity retention. A binder-free electrode (Si@CC@BP) using bucky paper further improved gravimetric and areal capacities while reducing weight and manufacturing complexity.

Next, I investigated how separator …


First-Principles Studies Of Electrical Polarization Effects In Ferroelectrics, Antiferroelectrics And Defects, Louis Alaerts May 2025

First-Principles Studies Of Electrical Polarization Effects In Ferroelectrics, Antiferroelectrics And Defects, Louis Alaerts

Dartmouth College Ph.D Dissertations

Over the last few decades, density functional theory (DFT) has emerged as a formidable tool in the field of computational material science. Not only has it become a complementary method approach to experiments by rationalizing the many complex properties of materials but its formidable predictive power can also be used to identify the most promising candidates for specific applications. Point defects in semiconductors have become an important platform for the development of quantum networks due to their ability to act as spin-photon interfaces. Spectral diffusion, the broadening of the optical emission line, can significantly impact the performance of these defect-based …


Low-Field Magnetoresistance In Nanocomposites Of La₀.₇Sr₀.₃Mno₃ And Metal Oxides, Nicholas K. Thiel-Hudson May 2025

Low-Field Magnetoresistance In Nanocomposites Of La₀.₇Sr₀.₃Mno₃ And Metal Oxides, Nicholas K. Thiel-Hudson

University Scholar Projects

Pure La0.7Sr0.3MnO3 (LSMO) exhibits colossal magnetoresistance (CMR) with large applied magnetic field over a narrow temperature range (intrinsic behavior), limiting its application to narrow temperature ranges. In contrast, the extrinsic CMR effect originates from inhomogeneities at larger length scales, such as grain boundaries and phase separation, where the structural features act as tunneling barriers, leading to a low-field magnetoresistance (LFMR) response, thereby expanding the application of LSMO into the low-field regime over a broader temperature range. In this work, the magnetotransport behavior of pure LSMO thin film is compared to the composite layered heterostructures of …


Assessment Of H2s-Induced Cracking Susceptibility In Steam Line Pipes And Weld Zones During Geothermal Well Construction, Riene Kaelamanda Pragitta, Yudha Pratesa May 2025

Assessment Of H2s-Induced Cracking Susceptibility In Steam Line Pipes And Weld Zones During Geothermal Well Construction, Riene Kaelamanda Pragitta, Yudha Pratesa

Journal of Materials Exploration and Findings

The susceptibility of steam line pipes, especially in the HAZ (heat-affected zone) and weldment areas, to hydrogen sulfide in the geothermal industry is crucial to understand from the early stages, particularly during construction. The combination of tensile stress from residual stresses after welding and metallurgical phase transformation makes the joint areas vulnerable to sulfide stress cracking. This condition becomes even more extreme when the equipment operates during the well stimulation phase. This research assesses the severity of H₂S-induced cracking using NACE MR0175 and ISO 15156-1 standards, focusing on the effects of pH and partial pressure of H₂S (pH₂S …


Effect Of Niobium Dopant On Zno Thin Films Prepared Via The Sol–Gel Spin Coating Method, Kevin Alvin Eswar, Nur Fairuz Rostan, Maryam Mohamad, Rabiatuladawiyah Md Akhir, Rosfayanti Rasmidi, Muliyadi Guliling, Najwa Ezira Azhar, Irmaizatussyehdany Buniyamin, Mohd Firdaus Malek, Mohamad Rusop Mahmood, Husairi Fadzilah Suhaimi, Saifollah Abdullah Mar 2025

Effect Of Niobium Dopant On Zno Thin Films Prepared Via The Sol–Gel Spin Coating Method, Kevin Alvin Eswar, Nur Fairuz Rostan, Maryam Mohamad, Rabiatuladawiyah Md Akhir, Rosfayanti Rasmidi, Muliyadi Guliling, Najwa Ezira Azhar, Irmaizatussyehdany Buniyamin, Mohd Firdaus Malek, Mohamad Rusop Mahmood, Husairi Fadzilah Suhaimi, Saifollah Abdullah

Makara Journal of Science

Thin films of zinc oxide (ZnO) and niobium (Nb)-doped ZnO were deposited on a glass substrate using the sol–gel spin coating method. Diethanolamine, isopropyl alcohol, and zinc acetate served as the stabilizers, solvent, and starting ma-terial, respectively. Niobium pentachloride was employed as the dopant source. Energy-dispersive X-ray analysis con-firmed Nb incorporation. Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and ultravio-let–visible spectroscopy (UV–Vis) analyses characterized the morphology, structure, and optics of the films, respective-ly. Both films, comprising nanoparticles, were visible in FESEM. Nb doping reduced the particle size from 44.2 nm to 35.8 nm. The XRD peaks at 31.23°, …


Fabrication Of Microscale Oxide Architectures On Silicon Via A Cmos-Compatible, Deposition-Last Process, Jamal A. Brown Jan 2025

Fabrication Of Microscale Oxide Architectures On Silicon Via A Cmos-Compatible, Deposition-Last Process, Jamal A. Brown

Material Science and Engineering Theses - Archive

This work explores the feasibility of integrating complex oxide devices on silicon using a CMOS-compatible, deposition-last approach. While previous demonstrations of this method have succeeded at larger scales, this study focuses on extending the process to microscale features, with lateral dimensions as small as two microns. The fabrication sequence begins with photolithographic patterning and reactive ion etching of the silicon substrate, followed by the deposition of a silicon nitride mask to delineate device regions. We then epitaxially grew SrTiO3 and La-doped SrTiO3 layers on top of the nitride mask via molecular beam epitaxy. Electrical transport measurements of the La:STO layer …


Beyond The Phonon Gas Model (Pgm): Unraveling The Unique Mechanistic Processes Dictating Thermal Transport In Highly Anharmonic And Disordered Materials, Sandip Thakur Jan 2025

Beyond The Phonon Gas Model (Pgm): Unraveling The Unique Mechanistic Processes Dictating Thermal Transport In Highly Anharmonic And Disordered Materials, Sandip Thakur

Open Access Dissertations

Thermal transport in nonmetallic solids has traditionally been described by the phonon gas model (PGM), in which heat is carried by weakly interacting phonon quasiparticles in an ordered crystalline lattice. However, this model breaks down in materials characterized by strong anharmonicity, dynamic disorder, or structural complexity, features prevalent in many next-generation materials used in energy conversion, optoelectronics, and thermal management. This dissertation investigates thermal transport in such complex materials, including metal halide perovskites (MHPs), covalent organic frameworks (COFs), metal organic frameworks (MOFs), and 2D-3D heterostructures, through large-scale molecular dynamics (MD) simulations and frequency-resolved spectral analyses.

In MHPs, the work reveals …


Characterization And Optimization Of Sand And Tung Oil-Based Resins For Binder-Jet 3d Printing, Daniel I. Ajiola Jan 2025

Characterization And Optimization Of Sand And Tung Oil-Based Resins For Binder-Jet 3d Printing, Daniel I. Ajiola

College of Graduate Studies: Theses & Dissertations

Binder-jet 3D printing as a transformative technology in additive manufacturing, offers the ability to fabricate complex structures with diverse materials. This thesis investigates the use of a sustainable tung oil-based resin to create composites, exploring the potential for an eco-friendly alternative to synthetic binders.

The aim of this research is to develop and characterize a bio-based resin formulation, using tung oil as the primary binder, for application in binder-jet 3D printing with sand as the reinforcement. The resin formulation was prepared by combining tung oil, n-butyl methacrylate, divinylbenzene, and di-tert-butyl peroxide in precise proportions, ensuring a balanced mixture that supports …


A Fault-Tolerant Exchange-Coupled Spin-Ensemble Qubit At Elevated-Temperatures, Aniruddha Chakraborty Jan 2025

A Fault-Tolerant Exchange-Coupled Spin-Ensemble Qubit At Elevated-Temperatures, Aniruddha Chakraborty

Theses and Dissertations

This thesis introduces a novel qubit architecture: the ferromagnetic exchange-coupled spin ensemble qubit (E-qubit), designed to address the noise-induced instability. In this work, the time evolution of the ensemble’s density matrix is studied using the Liouville–von Neumann equation. To benchmark against a single-spin qubit, the gate fidelity of an E-qubit is computed in the presence of thermal noise. Coherence time is also analyzed under identical thermal condition and a linear scaling is observed with qubit size . The results show that, at 6 K , the gate fidelity error (0.7 % ) of the seven- spin ensemble is an order …


Investigating The Roles Of Intrinsic Point Defects And Transition Metal Doping In Monolayer And Bulk Tis2, Patrick J. Keeney Jan 2025

Investigating The Roles Of Intrinsic Point Defects And Transition Metal Doping In Monolayer And Bulk Tis2, Patrick J. Keeney

UNF Graduate Theses and Dissertations

Within this thesis, the magnetic and electronic properties of various 1T-TiS2 systems are thoroughly examined using density functional theory (DFT) and scanning tunneling microscopy (STM). Formation energies and electronic implications of intrinsic point defects in bulk TiS2 and monolayer TiS2 are analyzed by approximating a computational monolayer of TiS2 as the surface layer of a bulk sample. This approximation is validated given that intralayer covalent bonding dominates interlayer van der Waals interactions. We conclude that the most energetically favorable intrinsic defects are Ti atoms settling above the outermost S plane and S vacancies. In addition, the …


Frustrated Quantum Magnetism: The Interplay Of Isotropic And Anisotropic Interactions With Application To Α-Rucl3, Evan M. Wilson Jan 2025

Frustrated Quantum Magnetism: The Interplay Of Isotropic And Anisotropic Interactions With Application To Α-Rucl3, Evan M. Wilson

UNF Graduate Theses and Dissertations

We investigate how anisotropic spin interactions, including Dzyaloshinskii–Moriya and Kitaev terms, manifest across quantum spin systems ranging from a single S = 1/2 dimer to molecular spin clusters and layered magnetic materials. Beginning with an exact analysis of the spin dimer, we demonstrate how singlet–triplet mixing induced by Dzyaloshinskii–Moriya interaction directly influences both thermodynamic observables and inelastic neutron scattering spectra. These microscopic fingerprints are then extended to trimer, tetramer, and tetrahedron geometries, where field-induced phase transitions and heat capacity anomalies reveal the interplay between isotropic Heisenberg and anisotropic Kitaev exchanges. In the frustrated zigzag honeycomb lattice, we show that a …


Synthesis And Characterization Of Doped Rare-Earth Zinc Alloys, Partha Das Jan 2025

Synthesis And Characterization Of Doped Rare-Earth Zinc Alloys, Partha Das

Graduate Theses/Dissertations

Rare-Earth-Zinc (RE-Zn) alloys doped with manganese represent a promising class of materials with diverse applications in magnetic, electronic, and thermoelectric devices. These alloys hold significant potential owing to the unique combination of rare-earth elements' properties with the versatility of zinc, augmented by manganese doping. In this study, I present the successful synthesis of ErMn0.2Zn11.8 alloys, achieved through self-flux method. The synthesized crystals were characterized using electron dispersive spectroscopy (EDS) and single crystal X-ray diffraction (XRD). Additionally, magnetic measurements were performed to investigate the magnetic properties. Future plans include DFT calculations and comparison study between Rare-Earth-Zinc alloys with …


Ge/Sige Quantum Wells: Material For The Post-Moore Era, Troy Alexander Hutchins-Delgado Dec 2024

Ge/Sige Quantum Wells: Material For The Post-Moore Era, Troy Alexander Hutchins-Delgado

Optical Science and Engineering ETDs

This dissertation demonstrates high-quality germanium quantum wells on a 200 mm silicon wafer platform, enabling novel device possibilities. Partnering with a commercial silicon-germanium epitaxy supplier, we obtained shallow, undoped germanium quantum wells with high-crystalline quality, confirmed through x-ray diffraction, secondary ion mass spectroscopy, high-resolution scanning transmission electron microscopy, and energy dispersive x-ray spectroscopy. Hall bar devices fabricated on single quantum wells revealed that surface preparation can tune transport properties while maintaining peak mobilities around 105 cm2V−1s−1. Manganese-germanide spintronic contacts were integrated via solid-state reaction, with contact quality assessed through Schottky diodes, transfer length …


Insulator-To-Metal Transition And Isotropic Gigantic Magnetoresistance In Layered Magnetic Semiconductors, Gokul Acharya, Bimal Neupane, Chia-Hsiu Hsu, Xian P. Yang, David Graf, Eun Sang Choi, Krishna Pandey, Md Rafique Un Nabi, Santosh Karki Chhetri, Rabindra Basnet, Sumaya Rahman, Jian Wang, Zhengxin Hu, Bo Da, Hugh O.H. Churchill, Guoqing Chang, M. Zahid Hasan, Yuanxi Wang, Jin Hu Nov 2024

Insulator-To-Metal Transition And Isotropic Gigantic Magnetoresistance In Layered Magnetic Semiconductors, Gokul Acharya, Bimal Neupane, Chia-Hsiu Hsu, Xian P. Yang, David Graf, Eun Sang Choi, Krishna Pandey, Md Rafique Un Nabi, Santosh Karki Chhetri, Rabindra Basnet, Sumaya Rahman, Jian Wang, Zhengxin Hu, Bo Da, Hugh O.H. Churchill, Guoqing Chang, M. Zahid Hasan, Yuanxi Wang, Jin Hu

Physics Faculty Publications and Presentations

Magnetotransport, the response of electrical conduction to external magnetic field, acts as an important tool to reveal fundamental concepts behind exotic phenomena and plays a key role in enabling spintronic applications. Magnetotransport is generally sensitive to magnetic field orientations. In contrast, efficient and isotropic modulation of electronic transport, which is useful in technology applications such as omnidirectional sensing, is rarely seen, especially for pristine crystals. Here a strategy is proposed to realize extremely strong modulation of electron conduction by magnetic field which is independent of field direction. GdPS, a layered antiferromagnetic semiconductor with resistivity anisotropies, supports a field-driven insulator-to-metal transition …


Substrate Interference And Strain In The Second-Harmonic Generation From Mose2 Monolayers, Sudeep Puri, Sneha Patel, Jose Luis Cabellos, Luis Enrique Rosas-Hernandez, Kaitlin Reynolds, Hugh O.H. Churchill, Salvador Barraza-Lopez, Bernardo S. Mendoza, Hiroyuki Nakamura Oct 2024

Substrate Interference And Strain In The Second-Harmonic Generation From Mose2 Monolayers, Sudeep Puri, Sneha Patel, Jose Luis Cabellos, Luis Enrique Rosas-Hernandez, Kaitlin Reynolds, Hugh O.H. Churchill, Salvador Barraza-Lopez, Bernardo S. Mendoza, Hiroyuki Nakamura

Physics Faculty Publications and Presentations

Nonlinear optical materials of atomic thickness, such as non-centrosymmetric 2H transition metal dichalcogenide monolayers, have a second-order nonlinear susceptibility (χ(2)) whose intensity can be tuned by strain. However, whether χ(2) is enhanced or reduced by tensile strain is a subject of conflicting reports. Here, we grow high-quality MoSe2 monolayers under controlled biaxial strain created by two different substrates and study their linear and nonlinear optical responses with a combination of experimental and theoretical approaches. Up to a 15-fold overall enhancement in second-harmonic generation (SHG) intensity is observed from MoSe2 monolayers grown on SiO2 when …


Surface Patterning On Zirconia Dental Implants Via Laser-Induced Shockwave Imprinting, Inomjon Majidov Aug 2024

Surface Patterning On Zirconia Dental Implants Via Laser-Induced Shockwave Imprinting, Inomjon Majidov

Masters Theses & Specialist Projects

Zirconia is rapidly becoming a preferred alternative to titanium in dental applications, primarily due to its aesthetic resemblance to natural teeth. This material’s tooth-like color avoids the aesthetic issues associated with the grey metal tint of titanium implants. Additionally, zirconia is hypoallergenic, making it an ideal choice for patients with metal sensitivities or allergies. Despite these advantages, zirconia generally exhibits lower biocompatibility and osseointegration compared to titanium implants. This study investigates laser-assisted, controlled imprinting technique on zirconia surfaces to enhance these properties. Our research used zirconia pellets, produced from powdered monoclinic zirconia pressed in a pellet press machine. Two methods …


Modeling Study Of Si3N4 Waveguides On A Sapphire Platform For Photonic Integration Applications, Diandian Zhang, Shui-Qing Yu, Gregory J. Salamo, Richard A. Soref, Wei Du Aug 2024

Modeling Study Of Si3N4 Waveguides On A Sapphire Platform For Photonic Integration Applications, Diandian Zhang, Shui-Qing Yu, Gregory J. Salamo, Richard A. Soref, Wei Du

Electrical Engineering and Computer Science Faculty Publications and Presentations

Sapphire has various applications in photonics due to its broadband transparency, high-contrast index, and chemical and physical stability. Photonics integration on the sapphire platform has been proposed, along with potentially high-performance lasers made of group III–V materials. In parallel with developing active devices for photonics integration applications, in this work, silicon nitride optical waveguides on a sapphire substrate were analyzed using the commercial software Comsol Multiphysics in a spectral window of 800~2400 nm, covering the operating wavelengths of III–V lasers, which could be monolithically or hybridly integrated on the same substrate. A high confinement factor of ~90% near the single-mode …


Settingsorder Article Reprints Open Accessarticle A Model To Account For The Effects Of Load Ratio And Hydrogen Pressure On The Fatigue Crack Growth Behavior Of Pressure Vessel Steels, Ashok Saxena, Kip O. Findley Aug 2024

Settingsorder Article Reprints Open Accessarticle A Model To Account For The Effects Of Load Ratio And Hydrogen Pressure On The Fatigue Crack Growth Behavior Of Pressure Vessel Steels, Ashok Saxena, Kip O. Findley

Mechanical Engineering Faculty Publications and Presentations

A phenomenological model for estimating the effects of load ratio R and hydrogen pressure PH2 on the hydrogen-assisted fatigue crack growth rate (HA-FCGR) behavior in the transient and steady-state regimes of pressure vessel steels is described. The "transient regime" is identified with crack growth within a severely embrittled zone of intense plasticity at the crack tip. The "steady-state" behavior is associated with the crack growing into a region of comparatively lower hydrogen concentration located further away from the crack tip. The model treats the effects of R and PH2 as being functionally separable. In the transient …


Laser 3d Printing Of Diamond-Based Composite Materials For Thermal Management Applications, Nada Kraiem Jul 2024

Laser 3d Printing Of Diamond-Based Composite Materials For Thermal Management Applications, Nada Kraiem

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

With the trend towards miniaturization of electrical equipment and the constant increase in power density in semiconductor devices, efficient heat management has become a major concern for researchers. Indeed, this technological evolution imposes increasingly strict constraints in terms of thermal dissipation, necessitating innovative solutions to ensure better durability and reliability of components. In this context, the use of composite materials offering high thermal conductivity (TC) and low coefficient of thermal expansion (CTE) compared to pure metals has become essential to address overheating issues in electronic components.

The utilization of advanced materials such as diamond (D), with exceptional TC and hardness …


Dual Light Emission Of Cssni3-Based Powders Synthesized Via A Mechanochemical Process, Xuan Huang, Xiaobing Tang, Xiyu Wen, Yuebin Charles Lu, Fuqian Yang Jul 2024

Dual Light Emission Of Cssni3-Based Powders Synthesized Via A Mechanochemical Process, Xuan Huang, Xiaobing Tang, Xiyu Wen, Yuebin Charles Lu, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Lead toxicity has hindered the wide applications of lead halide perovskites in optoelec- tronics and bioimaging. A significant amount of effort has been made to synthesize lead-free halide perovskites as alternatives to lead halide perovskites. In this work, we demonstrate the feasibility of synthesizing CsSnI3-based powders mechanochemically with dual light emissions under ambi- ent conditions from CsI and SnI2 powders. The formed CsSnI3-based powders are divided into CsSnI3-dominated powders and CsSnI3-contained powders. Under the excitation of ultraviolet light of 365 nm in wavelength, the CsSnI3-dominated powders emit green light with a wavelength centered at 540 nm, and the CsSnI3-contained powders …


Spin And Charge Transport In Metallic Ferrimagnets And Disordered Magnetic Oxides, Leopoldo A. Hernandez Jun 2024

Spin And Charge Transport In Metallic Ferrimagnets And Disordered Magnetic Oxides, Leopoldo A. Hernandez

Electronic Theses and Dissertations

Recent efforts have been exploring the use of thin film synthetic ferrimagnets and disordered magnetic oxides for applications in spintronic devices. Due to the antiferromagnetic exchange interaction, ferrimagnetic materials offer the ultrafast dynamics of the antiferromagnetic exchange, with a net magnetization that can be influenced externally. With two, or more, competing ferromagnet sublattices, interesting properties arise that depend on the final magnetic landscape after growth of the material and it’s inherent magnetic anisotropy energies. Properties such as magnetic compensation temperatures, and perpendicular magnetic anisotropy are attractive for applications in spintronic memory and logic devices, some already being implemented in MRAM …


Photodegradation Of Microplastics Through Nanomaterials: Insights Into Photocatalysts Modification And Detailed Mechanisms, Yiting Xiao, Yang Tian, Wenbo Xu, Jun Zhu Jun 2024

Photodegradation Of Microplastics Through Nanomaterials: Insights Into Photocatalysts Modification And Detailed Mechanisms, Yiting Xiao, Yang Tian, Wenbo Xu, Jun Zhu

Biological and Agricultural Engineering Faculty Publications and Presentations

Microplastics (MPs) pose a profound environmental challenge, impacting ecosystems and human health through mechanisms such as bioaccumulation and ecosystem contamination. While traditional water treatment methods can partially remove microplastics, their limitations highlight the need for innovative green approaches like photodegradation to ensure more effective and sustainable removal. This review explores the potential of nanomaterial-enhanced photocatalysts in addressing this issue. Utilizing their unique properties like large surface area and tunable bandgap, nanomaterials significantly improve degradation efficiency. Different strategies for photocatalyst modification to improve photocatalytic performance are thoroughly summarized, with a particular emphasis on element doping and heterojunction construction. Furthermore, this review …


Effects Of Ti Addition On The Characteristics Of Al-10zn-6mg-2si/Zro2 Composites Produced By Squeeze Casting, Qesha Diva Prameshvara, Pipin Indah Lestari, Bondan Tiara Sofyan May 2024

Effects Of Ti Addition On The Characteristics Of Al-10zn-6mg-2si/Zro2 Composites Produced By Squeeze Casting, Qesha Diva Prameshvara, Pipin Indah Lestari, Bondan Tiara Sofyan

Journal of Materials Exploration and Findings

Metal matrix composite (MMC) with 7xxx aluminum matrix is potential for ballistic applications due to the combination of strength, toughness, and light weight. Previous study successfully produced aluminum-based composites with SiC particles which were able to stop type III bullet, however cracks remained on back of the plate. Therefore, in this research, SiC was replaced by zirconia (ZrO2) due to its high fracture toughness. Ti-B grain refiner was added to further improve toughness through grain boundary strengthening mechanism. This research developed 5 vol.% ZrO2 strengthened Al-10Zn-6Mg-2Si composite with addition of Al-5Ti-1B grain refiner produced through squeeze casting …


Encapsulated 2d Materials And The Potential For 1d Electrical Contacts, Sarah Wittenburg May 2024

Encapsulated 2d Materials And The Potential For 1d Electrical Contacts, Sarah Wittenburg

Physics Undergraduate Honors Theses

The utilization of two-dimensional materials and heterostructures, particularly graphene and hexagonal boron nitride, have garnered significant attention in the realm of nanoelectronics due to their unique properties and versatile functionalities. This study focuses on the synthesis and fabrication processes of monolayer graphene encapsulated between layers of hBN, aiming to explore the potential of these heterostructures for various electronic applications. The encapsulation of graphene within hBN layers not only enhances device performance but also shields graphene from environmental contaminants, ensuring long-term stability. Experimental techniques, including mechanical exfoliation and stamp-assisted transfer, are employed to construct three-layer stacks comprising hBN-graphene-hBN. The fabrication process …


Spin Disorder Control Of Topological Spin Texture, Hongrui Zhang, Yu-Tsun Shao, Xiang Chen, Binhua Zhang, Tianye Wang, Fanhao Meng, Kun Xu, Peter Meisenheimer, Xianzhe Chen, Xiaoxi Huang, Piush Behera, Sajid Husain, Tiancong Zhu, Hao Pan, Yanli Jia, Nick Settineri, Nathan Giles-Donovan, Zehao He, Andreas Scholl, Alpha N'Diaye, Padraic Shafer, Archana Raja, Changsong Xu, Lane W. Martin, Michael F. Crommie, Jie Yao, Ziqiang Qiu, Arun Majumdar, Laurent Bellaiche, David A. Muller, Robert J. Birgeneau, Ramamoorthy Ramesh May 2024

Spin Disorder Control Of Topological Spin Texture, Hongrui Zhang, Yu-Tsun Shao, Xiang Chen, Binhua Zhang, Tianye Wang, Fanhao Meng, Kun Xu, Peter Meisenheimer, Xianzhe Chen, Xiaoxi Huang, Piush Behera, Sajid Husain, Tiancong Zhu, Hao Pan, Yanli Jia, Nick Settineri, Nathan Giles-Donovan, Zehao He, Andreas Scholl, Alpha N'Diaye, Padraic Shafer, Archana Raja, Changsong Xu, Lane W. Martin, Michael F. Crommie, Jie Yao, Ziqiang Qiu, Arun Majumdar, Laurent Bellaiche, David A. Muller, Robert J. Birgeneau, Ramamoorthy Ramesh

Physics Faculty Publications and Presentations

Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe3GaTe2, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights …


Gate-Controlled Supercurrent Effect In Dry-Etched Dayem Bridges Of Non-Centrosymmetric Niobium Rhenium, Jennifer Koch, Carla Cirillo, Sebastiano Battisti, Leon Ruf, Zahra Makhdoumi Kakhaki, Alessandro Paghi, Armen Gulian, Serafim Teknowijoyo, Giorgio De Simoni, Francesco Giazotto, Carmine Attanasio, Elke Scheer, Angelo Di Bernardo Apr 2024

Gate-Controlled Supercurrent Effect In Dry-Etched Dayem Bridges Of Non-Centrosymmetric Niobium Rhenium, Jennifer Koch, Carla Cirillo, Sebastiano Battisti, Leon Ruf, Zahra Makhdoumi Kakhaki, Alessandro Paghi, Armen Gulian, Serafim Teknowijoyo, Giorgio De Simoni, Francesco Giazotto, Carmine Attanasio, Elke Scheer, Angelo Di Bernardo

Mathematics, Physics, and Computer Science Faculty Articles and Research

The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction, named as gate-controlled supercurrent (GCS), has raised great interest for fundamental and technological reasons. To gain a deeper understanding of this effect and develop superconducting technologies based on it, the material and physical parameters crucial for the GCS effect must be identified. Top-down fabrication protocols should also be optimized to increase device scalability, although studies suggest that top-down fabricated devices are more resilient to show a GCS. Here, we investigate gated superconducting nanobridges made with a top-down fabrication process from thin films of …


Shorting At Long Duration: Impact Of Extended Discharge Capacity On Battery Solid Electrolytes, Ryan C. Hill, Amanda S. Peretti, Leo J. Small, Erik D. Spoerke, Yang-Tse Cheng Apr 2024

Shorting At Long Duration: Impact Of Extended Discharge Capacity On Battery Solid Electrolytes, Ryan C. Hill, Amanda S. Peretti, Leo J. Small, Erik D. Spoerke, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Long-duration energy storage (LDES) is critical to a stable, resilient, and decarbonized electric grid. While batteries are emerging as important LDES devices, extended, high-power discharges necessary for cost-competitive LDES present new materials challenges. Focusing on a new generation of low-temperature molten sodium batteries, we explore here unique phenomena related to long-duration discharge through a well-known solid electrolyte, NaSICON. Specifically, molten sodium symmetric cells at 110 ° C were cycled at 0.1 A cm−2 for 1–23 h discharges. Longer discharges led to unstable overpotentials, reduced resistances, and decreased electrolyte strength, caused by massive sodium penetration not observed in shorter duration discharges. …


Interfacial Magnetism And Anisotropy In Dirac And Weyl Semimetals, Noah Schulz Mar 2024

Interfacial Magnetism And Anisotropy In Dirac And Weyl Semimetals, Noah Schulz

USF Tampa Graduate Theses and Dissertations

Semimetals have gained intense interest recently due to their exotic magnetic and electronic properties. One of the most widely studied semimetals is graphene, a Dirac semimetal. The utilization of graphene in devices and sensors requires interfacing it with other materials, which may induce potentially strong interfacial effects. Furthermore, graphene alone does not possess magnetic order. Studying the interfacial effects between graphene and magnetic materials is therefore of great importance in the application of graphene to meet modern technological needs. Furthermore, by understanding the fundamental interfacial physics between graphene and magnetic materials, new properties can be unlocked, broadening the possible applications …