IMR - RUI: Acquisition of a Magnet Cryostat for Terahertz Spectroscopy and Education

Colgate University, Hamilton NY

Investigators

Abstract

This grant will fund the acquisition of a split-coil magnet cryostat that will be incorporated into an existing terahertz spectrometer. The initial experiments that will be performed using this spectrometer will examine the causes and effects of quantum tunneling of the magnetic moment in single molecule magnets. Quantum tunneling of the magnetic moment of Mn12-acetate was first reported in 1996, but its mechanism is still uncertain. This project will use a time-domain terahertz spectroscopy to probe a collection of these molecules during the tunneling process in order to provide a link between the local environment of the molecules and the tunneling probability. In a separate experiment, the process of relaxation will be observed through the observation of the THz pulse emitted when the molecules are suddenly heated above the blocking temperature, and it is anticipated that superradiance will be observed. In the longer term, this instrument will be used to study a wide variety of effects ranging from spin density waves to superconductivity, and it will also be used in upper level courses in solid state physics and materials science. Quantum tunneling is one of the hallmarks of quantum mechanics; its occurrence in a material guarantees that this material's properties cannot be explained by classical mechanics alone. In the twentieth century, the properties of very small quantum mechanical systems like atoms became fairly well understood. Now physicists are attempting to understand what happens when quantum mechanics becomes important for larger systems. The acquisition of this cryostat will enable experiments that will increase our understanding of quantum mechanical tunneling in the material Mn12-acetate, in which clusters of atoms behave as nanoscale magnets that can tunnel from one orientation to another. Besides being of fundamental scientific interest, this line of research may also lead to denser memory storage for computers or even to quantum computers. These possible future applications make these experiments particularly exciting for undergraduate physics students. This research award supports undergraduate research by allowing students at a liberal arts college to be involved in an exciting research project. It also will benefit students enrolled in upper level solid state physics and materials science courses by making it possible to perform laboratory experiments in a strong magnetic field so they can see directly the phenomena they are studying.