Non-Technical Abstract Materials that have simultaneous magnetic dipole and electric dipole order, called multiferroics, offer the potential for developing entirely new types of technological applications. Next generation multiferroic devices, including low-power/high-speed voltage switchable magnetic memory, may eventually replace current technologies for specific applications. However, before these concepts can be translated into real devices, it is necessary to understand the mechanisms giving rise to multiferroic order. The goal of this Faculty Early Career Development (CAREER) project at Wayne State University is to explain how magnetic and ferroelectric order can arise simultaneously at a single temperature. This project will investigate how ordered magnetic and electric dipoles interact in multiferroics under applied electric and magnetic fields using laser light and neutron scattering, among other techniques. These studies will help to explain how the magnetic and electric dipoles commun icate with one another in multiferroics, which will be crucial for designing better materials for innovative devices. This project will provide a platform for training the next generation of scientists through direct participation of graduate, undergraduate, and high school students in materials science research. Highlights from this exciting area of research will be incorporated into special topics lectures and demonstrations for Detroit area high school students.
This Faculty Early Career Development (CAREER) project at Wayne State University will investigate the simultaneous development of magnetic and ferroelectric order at a single phase transition in specific multiferroic oxides. The interplay between magnetic and ferroelectric degrees of freedom in these materials offers an extraordinary opportunity to study spin-charge coupling in "soft" materials that exhibit dramatic changes in their physical properties under externally applied fields. This project will explore the microscopic mechanisms for magnetoelectric couplings in multiferroics by studying low energy excitations under applied electric and magnetic fields using a variety of techniques including Raman and optical spectroscopy, neutron scattering, and thermodynamic characterization. Multiferroic thin film samples will be synthesized to investigate how a restricted geometry affects multiferroic order. This project will provide a platform for training the next generation of scientists through direct participation of graduate, undergraduate, and high school students in materials science research. Highlights from this exciting area of research will be incorporated into special topics lectures and demonstrations for Detroit area high school students.
The main objective of this award was to investigate how magnetic and electronic order an coexist is certain special classes of materials, called multiferroics. Systems that are both magnetic, like used in hard drives, and electrically ordered, like certain types of flash memory, can potentially be used to develop entirely new types of low power, high speed electronic devices. One of the significant outcomes to emerge from this project was the experimental confirmation that the temperature at which some of these special materials become magnetically ordered could actually be adjusted using an electric field. This observation has potentially important implications for designing new devices where the magnetization can be switched using an electric field. Another important outcome was the identification of new multiferroics materials. Although the particular systems found under this award only show magnetic and electronic order at very low temperatures, we can still learn about the physics of multiferroics by studying them, and use this information to help design new materials that can operate at room temperature. One further significant outcome was the serendipitous observation of novel magnetic and electronic properties in indium oxide. Tin doped indium oxide is widely used as a transparent conducting material in flat panel displays and solar cells. One of the objectives outlined in this award was to investigate how the optical properties of multiferroics change under an applied electric field. However, we found that the indium oxide films we used as the top electrode unexpectedly exhibited some magnetic properties. With further study, we found that even undoped indium oxide films could serve as transparent electrodes, and that these materials exhibited some interesting optical properties when exposed to UV light. While our understanding of this behaviour is still very limited, these results open the possibility of controlling electrical properties using light to complement the magnetic field control of electrical properties in multiferroics. Beyond increasing our understanding of novel electrical and magnetic materials, this award also provided important support for developing the next generation of researchers. Five graduate students have been trained in scientific research while associated with this project, along with five undergraduate students and nine high school students. The introduction to cutting-edge scientific research will benefit these students as they continue their careers in science and engineering. Additionally, general lectures on current developments in materials research, including nanotechnology, carbon nanotubes, and supernovae astrophysics, have been given to approximately 500 Metro Detroit high school students.
