Eric Fullerton - US grants

0906957
Fullerton

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

NON-TECHNICAL DESCRIPTION:
Nanomagnetism is one of the most active areas in science with a wide range of fundamental scientific problems as well as emerging technologies. Many magnetic devices are still in their infancy and a thorough understanding of the underlying materials and electronic properties and their effect on device performance will be essential for future technologies. The proposal explores important underlying structural, magnetic, and transport properties of new class of magnetic nanowires. This research will address fundamental issues of nanowire synthesis and magnetism at the nanoscale and train undergraduate and graduate students in important areas of nanoscience

TECHNICAL DETAILS:
The proposal explores underlying structural, magnetic, and transport properties of transition-metal oxide and core-shell metal/oxide nanowires (NWs). The NWs will be grown by chemical vapor deposition (CVD) resulting in single-crystal NWs of various phases and core-shell structures. The research will initially focus on understanding the growth and structural properties of NWs of transition metals and their oxides, and the formation of various core-shell structures. This will include a survey the CVD NW growth of the magnetic transition metals (Cr, Mn, Fe, Co and Ni) and their oxides with particular focus on understanding and controlling the phase formation, nucleation, and morphology. The research will include full structural and magnetic characterization of the NWs using advance electron and x-ray characterization techniques. The latter part of the proposal will focus on integrating these NWs into spin-transport devices to elucidate magnetic properties of composite materials at the nanoscale and to determine their potential for novel device applications. This research will address fundamental issues of a new class of metal-oxide composite NWs, determine their impact on future technologies, and train undergraduate and graduate students in materials synthesis, exploiting national user facilities for materials characterization, and the application of new materials to nanotechnology.

Nanomagnetism is one of the most active areas in science that presents us with a wide range of fundamental scientific problems as well as important and emerging technologies. Many spin-based devices are still in their infancy and a thorough understanding of the underlying materials and electronic properties and their effect on device performance will be essential for all future applications. The proposed research studies the relatively unexplored and emerging field of electric field control of metallic magnetic systems and exploits these effects in novel spin-based devices. The proposal will address the electric-field control of the intrinsic magnetic properties of transition metals and their alloys and compounds. The materials parameters to be studied include the magnetic moment density, magnetic anisotropy, Curie temperature and non-adiabatic spin-transfer parameter in magnetic transition-metal systems. All systems studied will be chosen such that they magnetically order near or above room temperature. Because these materials are conducting, the electric field (and its affect on magnetism) is confined to the near surface region; therefore this research will focus on thin films and heterostructured devices where the surfaces can dramatically affect the magnetic properties.

The intellectual merit of the proposal stems from the prospect of achieving a fundamental and predictive understanding of the electric-field modification of itinerant magnetism at the nanoscale. By combining skills in thin film synthesis and device fabrication, transport and magneto-optical measurements in device structures, and advanced characterization techniques, a complete data set will be obtained. These results will test current models of magneto-electric coupling in metallic systems and it is anticipated that interesting and unexpected new magnetic phenomena will emerge in this study.

The broader impact of the research will be both technical and educational. This research will address fundamental issues of magnetism and spin transport at the nanoscale and train undergraduate and graduate students in important areas of materials synthesis and characterization, device fabrication, nano-science, and nano-technology. An understanding of electric field effects on magnetism will have broad ranging impact from understanding the performance of current magnetic tunneling devices, to assessing the potential of electrical control in future spin-based electronics. The transformative goal is to provide the scientific underpinnings of next generation energy efficient, ultrafast, and ultrasmall magneto-electronic devices.

Nanomagnetism is one of the most active areas in science, with a wide range of fundamental scientific problems as well as important and emerging technologies. The main focus of this joint work between investigators at the University of California-San Diego, the Institut Jean Lamour and the Universite du Paris Sud-Orsay in France is on novel nanostructured magnetic materials for spintronics and, more precisely, for spin transfer torque based memory and spin logic devices. The research has three thrust areas: (i) development and characterization of novel magnetic materials suitable for magneto-electronics, (ii) integration of these materials into nanopillars, spin-injection and wire devices and (iii) study of the influence of both intrinsic (anisotropy, damping, magnetization) and extrinsic (size and shape of devices) parameters on the magnetization dynamic due to injected current at the nanoscale.

This research has prospects of achieving a fundamental understanding and ability to modify the properties of novel materials designed for spin-torque applications. This research addresses fundamental issues of magnetism, dynamics and spin transport at the nanoscale and trains undergraduate and graduate students in important areas of materials synthesis and characterization, device fabrication, nano-science, and nano-technology. An understanding and control of novel magnetic materials will have broad ranging impact from understanding the performance of current magnetic devices, to assessing the potential of current control of magnetism in future spin-based electronics.

This award is co-supported by the Office of International Science and Engineering.

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)"


Abstract
The objective of this research is to study fundamental electronic, photonic, chemical, and bio-logical behaviors of nanoscale structures relevant to future applications in next generation storage, energy harvesting, communications and computing, quantum communication and information proc-essing, superconductivity, and biomedical and biochemical sensing. The approach is to utilize nano-scale e-beam lithography in conjunction with other nanomanufacturing technologies to fabricate and characterize nanometer scale metamaterials, devices, and subsystems in which these new behaviors are expected to manifest themselves most clearly and can be exploited.
Intellectual merit: The proposed acquisition will enable investigation of smaller structures, finer features, and larger patterns than can be experimentally accessed today. Electronic and spin dif-fusion, a variety of magnetic behaviors, structural and chemical changes, superconducting decoher-ence, and many other phenomena that occur at nanometric length scales in common materials will be explored. Research projects are also planned in the areas of nanophotonics, metamaterials, quantum optics, quantum information, and nanomedicine.
Broader Impact: The creation of wealth through advances in nanoscale science and technol-ogy is at the heart of the 21st century economy. The impacts span multiple technical fields, including information systems, health care, energy, pollution monitoring, and chemical threat and explosive detection for homeland security applications. The UCSD Nano3 facility is serving a wide area of Southern California, and the proposed tool will benefit users throughout this geographic area. The project will also play a significant role in promoting education and development of human resources in science and engineering at the graduate and undergraduate levels, diversity and outreach.

TECHNICAL SUMMARY:
New functionality in nanomagnetic devices requires control of magnetic order at the nanometer spatial scale and sub-nanosecond temporal scale. Many spin-based devices are still in their infancy and a thorough understanding of the underlying materials and electronic properties and their effect on device performance will be essential for future applications. With support from the Division of Materials Research, this Materials World Network project builds on a strong existing collaboration between the PIs Fullerton and Lomakin in the US and Ravelosona and Mangin in France and focuses on the study of magnetization manipulation in novel and complex magnetic heterostructures with perpendicular magnetic anisotropy. The goal of this project will be on understanding the fundamental physics of magnetically coupled nanostructured materials and their application for spintronic devices that will enable energy-efficient magnetic memory, magnetic oscillators and spin logic devices. In particular, the research team is interested in developing approaches for actively controlling the response of composite materials through a combined experimental and micromagnetic approach. Each materials system will be optimized to enable new phenomena such as low critical currents and ultra-fast reversal, resonant behavior at the nanoscale and strain modified domain wall motion.

NON-TECHNICAL SUMMARY:
New scientific discoveries in nano-magnetism are enabling a range of emerging nanotechnologies in the areas of data storage, memories, information processing and energy efficiency in computing. Combining nano-magnetism with advances in semiconductor science and technology, that have until recently ignored the spin of the electron, it gives rise to the field of spintronics. Spintronics is ushering in a range of new sensors, memories, logic devices and providing a spin-vision for the electronics of the future. This Materials World Network project has the transformative goal to provide the scientific underpinnings for next generation energy efficient, ultrafast, and ultrasmall spintronic devices. The project will promote active exchange of students, faculty and researchers between institutions and student researchers will be exposed to a broad range of materials challenges using novel and sophisticated equipment. A key component of the proposal is to foster collaborations between leading international, industrial, and national user-facility scientists. This will not only strengthen the scientific excellence and broaden the impact of the research, but it will also provide important educational and post-graduate career opportunities for both graduate and undergraduate students. This project will support innovative and sustainable partnerships between French and US research centers and institutions of higher education.

NON-TECHNICAL DESCRIPTION: Nanomagnetism is one of the most active areas in science with a wide range of fundamental scientific problems as well as important and emerging technologies. New functionality requires control of magnetic order at the nanometer spatial scale and sub-nanosecond temporal (time) scale. Within this project, the interplay of strain and magnetism in nano-structured magnetic materials and the control of these properties to yield new functionality are being studied. Researchers are combining novel materials engineering and synthesis approaches with advanced synchrotron techniques for three-dimensional strain and piezoelectric imaging to probe the response of nanoscale systems to perturbation by magnetic and electric fields. The goal is to gain a fundamental understanding of strain in nanostructured materials. This project will benefit from strong collaborations with international, national user facility and industrial scientists. This interactive approach provides important educational and post-graduate career opportunities for both graduate and undergraduate students. In addition the project includes outreach efforts aimed at middle-school and high-school students via the Young Physicist Program at the University of California San-Diego (UCSD) and The Winston School in Del Mar, and outreach at the undergraduate level, via UCSD's Society of Physics Students.

TECHNICAL DETAILS: The first part of the project probes the fundamental magnetostrictive response of nano-materials of magnetic transition metals and transition-metal oxides. In doing so, thin-film heterostructures, core-shell nanowires and nanoparticles are being imaged by coherent X-ray diffraction techniques to obtain quantitative three-dimensional nano-scale images of the magnetostriction and then link the magneto-elastic response to the microstructure and micromagnetic states. This research then uses strain to obtain and optimize giant magnetostriction in nanostructures materials. In the next stage, materials are being integrated into devices to actively control the strain, magnetic, transport and magneto-optical responses with a combination of magnetic and electric fields. Finally, the response of strain at the ultrafast timescales using synchrotron-based pump-probe techniques probes the systems with electric, magnetic or thermal pulses and images the response with nano-focused and/or coherent X-ray diffraction techniques.

The San Diego Nanotechnology Infrastructure (SDNI) site of the NNCI at the University of California at San Diego offers access to a broad spectrum of nanofabrication and characterization instrumentation and expertise that enable and accelerate cutting edge scientific research, proof-of-concept demonstration, device and system prototyping, product development, and technology translation. Nanotechnology is the cornerstone of many industry sectors and a rich source for scientific discoveries and innovations. Using nanotechnologies, scientists are likely to find solutions for the most important challenges in health, communications, energy, and environment. Nanotechnology is multidisciplinary by nature and requires highly sophisticated tools and deep expertise, often unavailable or unaffordable by individual research labs and businesses. The SDNI site will offer state-of-the-art knowhow, tools, and services of nanotechnologies to all interested users across the nation in a user friendly, timely, and cost effective manner. The site will also become a nanotechnology provider to create and develop new nanotechnologies and bring them to its users. The goals of the site are to serve a large number of academic, industrial, and government users, to transfer enabling nanotechnologies from research laboratories to the general user community, to educate and train future generations of scientists and engineers in nanotechnology, and to bring nanoscaled research experience to college students and K-12 students, especially underrepresented minority students, to prepare them for STEM careers.

The SDNI site will build upon the existing Nano3 user facility and leverage additional specialized resources and expertise at the University of California at San Diego. The SDNI site is committed to broadening and further diversifying its already substantial user base. The proposed strategic goals include: (i) providing infrastructure that enables transformative research and education through open, affordable access to the nanofabrication and nanocharacterization tools and an expert staff capable of working with users to adapt and develop new capabilities, with emphasis in the areas of NanoBioMedicine, NanoPhotonics, and NanoMagnetism; (ii) accelerating the translation of discoveries and new nanotechnologies to the marketplace; and (iii) coordinating with other NNCI sites to provide uninterrupted service and creative solutions to meet evolving user needs. Significant growth is anticipated in the number and variety of local and regional users in the academic, government, and industrial sectors. Discoveries made by users of the SDNI site have the potential to create transformative change in fields as diverse as medicine, information technology, transportation, homeland security, and environmental science, leading to improved healthcare, faster communications, safer transit, and cleaner water and air. To develop a more diverse and productive scientific workforce, the SDNI site will expand undergraduate and graduate training programs including REU opportunities to train 900 students over five years. Through an RET program and other activities, the site will work to increase the number of students from underrepresented minority groups who pursue studies and, ultimately, careers in STEM disciplines.

Nontechnical description: Photonic metamaterials are artificial constructs whose optical characteristics may be engineered by altering their geometrical structure, as well as their chemical composition. In this project, the research team explores new phenomena that arise when structural features of the metamaterials are of only several nanometers in size. On such a small scale, traditional optical properties such as color and sheen are no longer discernible. Instead, the properties of the materials may now be precisely tuned by carefully varying their nanoscale structure. The overarching goal of this project is to conduct basic science and engineering research on such precision-structured metamaterials, and elucidate their potential applications. This study particularly addresses fundamental aspects of electronic and optical characteristics of nanoscale metamaterials. In addition, undergraduate and graduate students receive hands-on training in the fields of nanoscience and nanotechnology, materials synthesis, characterization, and device design. Achieving a fundamental understanding of artificial optical materials and their fabrication is anticipated to have broad ranging impact on assessing their potential in new optical devices.

Technical description: This project addresses the prospects for achieving fundamental understanding of a new class of hyperbolic metamaterials at the quantum level, and the ability to engineer and fabricate such structures. In particular, the research team is interested in developing quantum engineering methodologies through an approach which combines materials optimization, detailed optical studies and theoretical modeling. The project fosters a systematic investigation, starting from ab-initio modeling of thin films, followed by studies of multilayered systems, and subsequently a detailed study of patterned nano-photonic structures and devices. By combining skills in thin film synthesis, device fabrication and characterization, ultrafast optics and nano-photonics a comprehensive data set is obtained. Given the current trends for nanophotonics, device miniaturization and photonic-electronic integration, the ability to engineer new photonic materials is expected to significantly extend current applications of existing devices, enabling yet unforeseen implementations of quantum photonic metamaterials.

NON-TECHNICAL SUMMARY

Whereas the vast majority of the world’s digital information is processed using nanoscale devices to manipulate the charge of electrons, most of this information is stored using the spins of electrons in the form of nanoscale magnetic domains. Recent advancements in magnetic materials and nano-characterization techniques have revealed nanoscale magnetic knots formed by the spins of many electrons. Topology is a property to describe the different types of magnetic knots, and could enable new types of electronic devices for sensing, processing, and storing information. This Collaborative Research project develops abilities to produce, manipulate, and characterize these knotted magnetic features. The project engages a wide age range of students on meaningful research, including training middle-school-aged summer camp students to use an electron microscope to search for nanoscale “magnetic bow ties”. The project promotes active exchange of students, faculty and researchers between institutions, and both undergraduate and graduate student researchers are educated in a broad range of materials challenges and nanoscale measurement techniques using novel and sophisticated equipment. A key component of the proposal is to foster collaborations between leading international and industrial scientists to provide international research experience for graduate students. This will not only strengthen the scientific excellence and broaden the impact of the research, but it will also provide important educational and post-graduate career opportunities for both graduate and undergraduate students.

TECHNICAL SUMMARY

New functionality in nanomagnetic devices requires control of magnetic order at the nanometer spatial scale. Many spin-based devices are still in their infancy and a thorough understanding of the underlying materials and electronic properties and their effect on device performance will be essential for future applications. This Collaborative Research proposal builds on a strong existing collaboration between the PIs Fullerton and McMorran, international and industrial partners, and Harvey Mudd College to achieve a fundamental understanding of and ability to control the topological spin order in nano-structured magnetic materials and devices. The research is particularly interested in the design, manipulation and imaging of thin-film materials that exhibit complex 3-D topological states and defects such as chiral hybrid domain walls, chiral helixes, skyrmions, bi-skyrmions, antiskyrmions and hopfions. The morphology of the domains and defects depends sensitively on the underlying materials properties as well as on the application of magnetic fields, field history, and temperature where domains can arrange in metastable configurations including various topological defects. The team will develop and apply several recent methods in advanced electron microscopy to characterize the structure of these topological states, as well as their behavior under the influence of ultrafast fields. Summer curriculum is developed for the 7-12th grade and undergraduate levels to educate students on the use of nanoscale tools, and engage them in meaningful supervised research.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.