New and higher-performing materials play a key role in enabling new technology. Central to achieving this goal is a detailed understanding of the impact that structure and composition have on physical properties. To that end, the research conducted in our group broadly focuses on understanding the interplay between spin, charge, and lattice degrees of freedom in the solid state so as to better design new and improve existing functional materials. A few examples of which are outlined below.
We use a large variety of synthetic methods to prepare new materials; including high-temperature ceramic as well as hydrothermal routes. We place equal emphasis on the preparation of materials and their complete physical characterization which includes an accurate determination of: the underlying crystal structure, magnetism, electrical transport, dielectric properties, and electrochemical performance. We also make extensive use of a variety of density functional theory (DFT) computational tools in order to understand the nature of chemical bonding in these materials.
New Materials for Li-ion Batteries
Facing dwindling supplies of fossil fuels and skyrocketing prices associated with such shortages, the most important challenge our society must overcome is how we will establish a sustainable and environmentally benign energy infrastructure. The challenge as it stands today is not to understand how to convert and store the energy we will need, but rather what materials we will use to produce and manage the energy required while making world-wide implementation a reality. Despite fervent research efforts, lithium batteries, which have been heavily investigated for nearly forty years, have been primarily restricted to small consumer devices such as laptops and cellphones. However, provided that the cost, safety, and energy density can be further enhanced, these batteries have great potential in the fields of automotive transportation and electrical grid storage. In order to circumvent intrinsic materials limitations, it becomes increasingly clear that we must continue the search for new compounds if this technology is to approach feasibility in large scale applications. To help meet this demand, our group works on the preparation and elaboration of new compounds for use Li-ion batteries. In particular, we focus on modifying the electronegativity of constituent anions as a way to increase the open circuit voltage of individual cells and thereby increase their power density.
Frustrated Magnetism and Magnetodielectricity
Magnetodielectrics are materials in which the dielectric properties couple to changes in the magnetic order. The ability to find and design new single-phase materials which exhibit this kind of coupling has significant technological implications in the development of magnetic sensors and field-tunable dielectrics. One route which has shown great promise for the identification of such materials is investigate materials which exhibit magnetic frustration. Frustrated systems are those in which the spin, charge, or orbital degrees of freedom are unable to attain a unique low-energy ground state due to either competing interactions or the geometry of the lattice. Our group focuses on developing ways to understand and thereby gain some control over the degree of frustration in these systems with the hope of identifying new magnetodielectric materials.