Correlation Among the Size, Atomic Arrangement, and Magneto-Optical Properties in Rare Earth Nanocrystals

Vanderbilt University, Nashville TN

Investigators

Abstract

Technical Abstract This project aims at determining how geometry and magneto-optical effects are correlated in a class of Heisenberg ferromagnetic nanomaterials, rare earth chalcogenide nanocrystals. Monodisperse nanocrystal of EuS, EuO and EuTe with sizes ranging between less than 2.0 nm (quantum-confined) to about 20 nm (nanocrystals) will be produced using a thermolysis procedure of single source precursor under nitrogen atmosphere. Magnetic and magneto-optical properties of the nanocrystals will be studied as functions of crystal size, crystal boundary characteristics and local atomic separation within the crystals themselves. The studies will be carried out by means of magnetic, optical and x-ray diffraction, techniques. The different tasks and project activities are designed with the goals to encourage the participation of underrepresented groups in science, contribute to science infrastructure and integrate science and education. Educational/research programs will be available to allow the participation of students ranging from high school to graduate level. These are in particular NSF?s Research Experience for Undergraduates (REU) and the Vanderbilt Center for Science Outreach High School Summer Internship. Intellectual infrastructure of this project is expected to aid in the development of new magnetic and magneto-optical nanodevices. Non-technical Abstract Nanotechnology continues to produce important and unsuspected results, many of them for the benefit of mankind. Its potential is still being exploited and its development will likely continue within the foreseeable future. As structures and devices become smaller and smaller, the properties of the materials from which they are made change?in many instances dramatically?and differ from the properties of the bulk. Understanding these properties is very important to continue the development of technologies and the understanding of physical phenomena at smaller and smaller scales. On this light, this project aims at determining how geometry and magneto-optical effects are correlated in a class of ferromagnetic nanomaterials: the rare earth chalcogenides. When prepared using the specific methods of this project, these materials form in very small nanoparticles, some of which are so small that cannot be understood using classical physics, but require the use of quantum mechanics. Others (somewhat bigger, but still at the nano scale) form nanocrystals whose physical properties can be vastly different from those more familiar crystals formed by the material in bulk. The project seeks to understand the physics behind these differences by using magnetic, optical and x-ray diffraction, techniques. The intellectual infrastructure of this project is therefore expected to aid in the development of new magnetic and magneto-optical nanodevices sometime in the future. The different tasks and project activities are designed with the goals to encourage the participation of underrepresented groups in science, contribute to science infrastructure and integrate science and education. Educational/research programs will be available to allow the participation of students ranging from high school to graduate level. These are in particular NSF?s Research Experience for Undergraduates (REU) and the Vanderbilt Center for Science Outreach High School Summer Internship.