Julia Chan, Ph.D. - US grants

This proposal was submitted in response to the solicitation "Nanoscale Science and Engineering" (NSF 01-157), category NIRT. Novel electrodeposited nanostructured multilayered alloys for microelectromechanical systems (MEMS) will be developed. High sensitivity magnetic sensors and hard materials for micro-cutting tools and molds will be fabricated. Compositionally modulated multilayered alloys offer a variety of improved properties including enhanced giant magnetoresistance for thin film magnetic sensors, and superior hardness for high aspect ratio microdevice components, compared to their coarser microstructural counterparts. It is expected that the nanometric feature of the layers will contribute to a change in the physical properties and microstructure. Electrochemical processing will be used to fabricate both thin and thick nanomaterials with pulsed waveforms.

Magnetic, electronic and mechanical properties will be examined, including electrical resistivity, magnetoresistivity, DC/AC magnetization and susceptibility, and hardness.
Investigators at LSU/CAMD, Argonne and Brookhaven National Labs will work
together towards characterization of the electrodeposited nanolayered alloys with student
involvement at the national labs. Student outreach will be conducted through PI participation in the Society of Women Engineers and the National Organization for the Professional Advancement of Black Chemists and Chemical Engineers. The proposed electrodeposition techniques have the potential to significantly improve the quality of multilayered nanostructures, especially those with curved and recessed substrates.

This project is focused on the synthesis and structural characterization of intermetallic heavy fermion superconductors. It is our goal to correlate magnetic properties with rare earth cations, main group, transition metals, and crystal chemical relationships. Through cooperative efforts between Louisiana State University (LSU), Los Alamos National Laboratory (LANL), the National Institute of Standards and Technology (NIST), and Oak Ridge National Laboratory (ORNL), high quality samples will be produced and characterized, and detailed magnetic and transport measurements will be made. The training of undergraduate and graduate students will emphasize carrying out investigations ranging from basic sample preparation all the way through to measurement techniques and data interpretation. A community education outreach program will involve high-school science teachers working in the PI's lab during the summer. This will allow these teachers to experience research and the scientific method in action making a very positive impact on local physical science education. In addition, LSU students will perform chemistry demonstrations in K-12 school classrooms.

This proposal is aimed at the exploration of the rewarding boundary between crystallography and the systematic study of structure-dependent properties such as superconductivity and magnetism in rare earth intermetallics. With the combination of synthesis, characterization, and measurements of properties of new materials, this research will create a basic understanding of the interplay of superconductivity and magnetism allowing the tailored design of new materials useful for information technology. Students will measure magnetic and electronic/ transport properties of polycrystalline and single crystal materials at Louisiana State University (LSU) gaining a broader and more diverse scientific background as they collaborate within the LSU scientific community and national laboratories. LSU students will also perform chemistry demonstrations in East Baton Rouge K-12 schools. In addition, a high school teacher will perform research in the group and return to the classroom during the academic year with new scientific perspectives, as related to new materials for information technology.

This project aims to grow and characterize single crystals of rare earth intermetallics, correlate their structure and properties, and look for new phenomena. The synthesis of these materials in single crystalline form will be addressed as one of the primary driving forces of basic research in the chemistry of new materials. To understand physical properties of novel materials clearly, it is essential to grow crystals that are large (at least 2-5 mm3) and of high quality for the measurement of properties. Training future crystal growers to interact with collaborators in national labs as well with international scientists is vital to advancing materials research. Students involved in this project will continue to be involved in educational activities such as doing hands on demonstrations and developing materials-related demonstrations. The PI will also continue with outreach efforts to under-represented minorities at the high school, undergraduate and graduate level.

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The exchange mechanisms and spin correlations mediated by itinerant electrons have attracted much interest due to the emerging field of spin electronics. A goal for this project is to grow single crystals of cerium and ytterbium and ytterbium intermetallic phases in the lanthanide-copper-X (X = gallium, tin, antimony) systems in which the phenomena and/or implications of heavy fermion behavior, superconductivity, magnetism and/or magnetoresistance may be observed and studied. New families of intermetallics will be investigated with the motivation of correlating structure and properties, in particular uncovering emergent ordered phases arising from quantum fluctuations. Students will perform hands on demonstrations and will develop materials-related demonstrations for incorporation into Chem Demo programs. The PI will also develop outreach projects for under-represented minorities at the high school, undergraduate and graduate level. Students will interact with collaborators in national labs as well with international scientists.

TECHNICAL SUMMARY:

This proposal funds for a symposium entitled ?Synthesis and Applications of Intermetallic Compounds? at the 238th American Chemical Society National Meeting, to be held in Washington DC from August 16-20, 2009. A broad spectrum of important topics in modern intermetallics covered:
? Synthesis of intermetallics for energy (e.g. hydrogen storage and thermoelectrics) and magnetic applications, along with novel synthetic approaches and strategies (including synthesis of nanoparticles, and use of flux, microwave synthesis, metathesis, etc).
? Innovative chemical strategies and understanding of intermetallics (including intermetallic nanomaterials, new chemical bonding paradigms)
? New characterization techniques and novel physical properties of intermetallics are also presented.
Chemists interested in the synthetic design of intermetallics will also have the opportunity to learn about the potential physical properties of new materials at different length scales (from nanoscale to bulk phases). Theoretical chemists will be exposed to state-of-the-art synthetic design capabilities.


NON-TECHNICAL SUMMARY:

This proposal funds a symposium with three oral sessions and one poster session entitled ?Synthesis and Applications of Intermetallic Compounds? at the 238th American Chemical Society National Meeting, to be held in Washington DC from August 16-20, 2009. The symposium will focus on synthesis, chemistry, and applications of intermetallics that directly impact a wide range of areas, including energy-related and alternative energy applications, such as superconductivity, thermoelectrics, and materials with novel mechanical properties. The potential impacts of this symposium are the interactions of high profile scientists with junior faculty and students. In this symposium, over half of the speakers are women and underrepresented minorities. In addition, many students and postdocs of the invited speakers are presenting their work in a poster session.

TECHNICAL SUMMARY:
The search for materials with desired properties concomitantly relies on the discovery of new materials and the subsequent growth of large single crystals. To unequivocally determine the material's innate properties, large single crystals must be grown such that detailed studies can be completed. The growth of high quality single crystalline materials allows the determination of intrinsic properties and for fundamental correlation between structures and unusual magnetic and electrical properties. This research, supported by the Solid State and Materials Chemistry program is focused on synthesizing materials of the ternary intermetallics Ln:M:X (Ln = lanthanide, M = transition metal, X = Al, In) to correlate crystal chemistry and physical properties. The effort is focused on growing high quality single crystals of four families of intermetallics to study the competition of magnetic fluctuations and unusual magnetism, targeting the CeCr2Al20, Ho6Mo4Al43, ThMn12, and YbFe2Al10 structure types. These structures consist of high coordination polyhedra and serve as models for investigating the role of two sublattices and packing on magnetism.

NON-TECHNICAL SUMMARY:
The search for materials with desired properties concomitantly relies on the discovery of new materials and systems. The proposed work, supported by the Solid State and Materials Chemistry program involves the synthesis and characterization of novel materials containing rare earth transition metals to understand new physical phenomena. The group's effort is aimed at growing large single crystals to perform measurements and determine intrinsic behavior of new compounds with potential energy applications. The PI's group will continue collaborations with scientists in Japan as there is a natural and mutually beneficial synergy of synthesis and characterization that exists between research groups, as well as a common mentoring of graduate and undergraduate students between the research groups. Research and teaching are integrated by incorporating crystallography and materials science throughout two courses (General Chemistry and Advanced Inorganic Chemistry). The partnership with a local elementary school will lead to continued enhancement in curriculum development. The Chan group will continue to develop hands-on materials-related demonstrations for incorporation into LSU Chem Demo program. An additional aim of this proposal is to involve high school chemistry and physics teachers for a summer research experience in the laboratory. This will offer an invaluable tool to boost teachers' involvement in the sciences and their understanding of how their discipline relates to the children in the classroom.

TECHNICAL SUMMARY
The "Progress and Challenges in Crystal Growth Design and Characterization Symposium" at the 2012 fall National American Chemical Society meeting in Philadelphia PA, partly funded by the Solid State and Materials Chemistry Program, will bring together scientists from the fields of inorganic chemistry, solid-state chemistry, condensed matter physics and electrical engineering to examine important topics of research. Discovery of new crystalline materials and the growth of high-quality single crystals have potential impact on many sectors, including energy production, energy storage, national security and information technology. However, the National Research Council of the National Academies, Committee for the Assessment of and Outlook for New Materials Synthesis and Crystal Growth, have identified crystal growth and discovery of new materials as areas where the United States is rapidly losing its footing. The committee also pointed out that the United States can only excel in this area if there is a critical mass of young scientists who have the interdisciplinary knowledge and training necessary to succeed in this field of research. Yet they also discovered that there is a marked decline in educational and training opportunities in this country in the areas of crystal growth and preparation of new materials, while these opportunities are increasing in other parts of the world, for example Europe and Asia. This symposium helps to call attention to this problem and also to meet this need by serving to educate young researchers on the research activities of others in the area.

NON TECHNICAL SUMMARY
This symposium will provide younger scientists, including undergraduate students, graduate students and postdoctoral fellows the opportunity to present their work in crystal growth and new materials synthesis. It will also allow younger scientists a chance to interact with established researchers in the field. Gathering people with different approaches to similar research problems will spark collaboration and the sharing of ideas. Approximately 35% of the invited speakers are from primarily undergraduate institutions and about 40% of the invited speakers are women. Faculty at all levels (assistant, associate and full professor) will participate in the symposium, as well as individuals from industry and national laboratories.

Nontechnical Abstract
With support from the Solid State and Materials Chemistry program in the Division of Materials Research, the primary focus of this proposal is to grow single crystals of lanthanide intermetallics with unusual magnetic and electrical properties for energy applications. The growth of single crystals is necessary to determine properties of novel magnetic materials. This is motivated by understanding unusual magnetism thereby decreasing our dependence on critical elements. The single crystal growth aspects of this proposal will enable students involved in the project to determine and characterize the structures of new materials and elucidate intrinsic properties of the new compounds.

Technical Abstract
The goal of this project is to discover and grow high quality single crystals of intermetallics for magnetic, electrical, and transport applications, in particular compounds with unusual ground states and competing magnetic interactions. Several classes of materials containing lanthanide, mid-transition metals, and Group 13-14 elements are proposed. The research team will synthesize compounds adopting the CaCo2Al8 structure type and determine the structural stability of LnMxGa3, Ln4MGa12 (Ln = Lanthanide, M = Cr, Mn, Fe), and ScFeGa5 allowing for the creation of a delicate balance between dissimilar ground states, especially in materials supporting strongly correlated or quantum-mechanical interactions among the electrons. Furthermore, the growth of complex stannides will enable the study of compounds exhibiting low lattice thermal conductivities. Undergraduate and graduate students involved in this project will have the opportunity to synthesize and characterize new compounds and measure magnetic and electrical properties of the compounds they discovered in the lab.

This award supports the University of Texas at Dallas to acquire a state of the art X-ray diffraction tool for determination and understanding of the crystal structure of new materials in the fields of low power electronics, energy storage, superconductors, organic electronics, nanotechnology, flexible electronics, photovoltaics, optoelectronics, and environmental catalysts. Crystal structure plays a major role in each of these important applications as it determines the mechanical, toxicity, reactivity, and electronic properties of the new materials. The remarkable advances over the past half century in the fields of computing, engineering, medicine, and energy would not have taken place had it not been for the creation of "materials by design" that is only possible when the structure of materials and their correlation to material properties are well known. UT-Dallas has state of the art facilities for materials synthesis by a wide range of technologically relevant processes in addition to advanced characterization tools. Therefore, this new instrument, which allows a precise determination of the structure of materials grown by the PI, will allow them to study the effect of processing conditions on materials structure and, in turn, determine the materials properties. The instrument will also play a significant role in the education of graduate and undergraduate students in a wide range of disciplines; it will be open to users from outside of the university fostering new collaborations in the Dallas-Fort Worth metropole and around the country.

The instrument is a Rigaku SmartLab high-resolution, ultra-high speed X-ray diffractometer for the structural analysis and crystal quality determination of bulk and thin-film organic and inorganic materials for nanoelectronic and energy applications. The new instrument will be housed in the Natural Science and Engineering Research Laboratory (NSERL) and will complement existing materials synthesis and device fabrication capabilities in dedicated labs and shared user facilities at UT-Dallas. The new diffractometer will significantly enhance in research high quality single crystal 2-dimensional semiconductors for high performance and low power nanoelectronic applications, in intermetallic and oxide layered materials that can exhibit a range of properties from unusual magnetism to superconductivity and more. In these fields and others the quantification of thin-film crystal quality and the orientation of grains in polycrystalline samples in reduced dimensions are crucial to understanding the process-structure-property relationships. The ability to determine crystal quality and carry out high-speed pole figures for texture analysis opens new research avenues for a wide number of investigators and students. The acquisition of a high-resolution and ultra-high speed X-ray diffractometer will greatly enhance the research of current and potential materials and device researchers within UT-Dallas and across the Dallas-Fort Worth Metroplex as well as dramatically transform important research and educational efforts. The instrument will be used to improve student education and training through hands-on access to new techniques and complement classroom learning.

Non-Technical Abstract

The search for magnetic and thermoelectric materials with desired properties relies on the discovery of new metal-based compounds, and also requires that the materials can be grown as high quality single crystals. The research strategy of this project, funded by the Solid State and Materials Chemistry program in the Division of Materials Research, is motivated by magnetocalorics for refrigeration, thermoelectrics for converting wasted heat to electricity, and magnetic materials for next generation quantum computing. This project provides training opportunities for undergraduate and graduate students in a multidisciplinary environment. They gain insights into the design of novel materials. The partnership between the research group and the scientific community fosters continued enhancement in science learning. The principle investigator's group also works with a high school team of students and industrial partners as part of the "Young Women in Science" group and "Nanoexplorers", pursuing materials science projects. Additionally, the Chan group performs hands-on materials science-related demonstrations for the general public.


Technical Abstract

Discovering new metal-based compounds and linking their chemical structures to magnetic, electrical, and thermal properties for energy applications is the goal of this research, which is supported by the Solid State and Materials Chemistry program in the Division of Materials Research. The growth of large single crystals is necessary to unequivocally determine the material's innate properties. With this award, the principle investigator studies several classes of materials containing lanthanide, mid-transition metals, and Group 14-15 elements. The motivation for this effort is to correlate the structural details to predict physical properties. The efforts focus on growing high quality single crystals of the Tb117Fe52Ge112 (Ln = Gd, Dy) and Ln30Ru4Sn31 structure types, which allows the study of structural complexity, complex magnetism, and low lattice thermal conductivity. In addition to studying structural phase stability of stannides and germanides, atomic displacement parameters are correlated with electrical resistivity as a testbed for predicting electrical properties of materials. Inspired by the emergence of spin glass and itinerant magnetism in Pr2Fe4Sb5, the magnetic and electrical properties of Ln2Fe4-xMxSb5 (Ln = La, Ce, Pr, Sm; M = Mn, Co, Zn) are also investigated. Compounds of this structure type are of particular interest because of the Fe-triangular subunits coupled with Sb-square nets, two features found in several highly correlated systems. Students involved in the proposed project will also have the opportunity to work with collaborators at other institutions and national laboratories. The principle investigator's entire research group is involved in mentoring students at different levels, including undergraduates throughout the academic year and high school students in the summer.