9733848 Beauchamp This is a CAREER award to a female scientist at a predominantly undergraduate institution. The research will explore the static and dynamic properties of magnetic and superconducting systems which exhibit quantum effects and disorder. One system consists of random ferromagnetic or antiferromagnet quantum spin chains which can be described by a one-dimensional, S=1/2 Heisenberg Hamiltonian with quenched disorder. The second system consists of ordered and disordered two-dimensional Ising antiferromagnets, with both short range and long range interactions. The two- dimensional Ising system in a transverse field is the simplest system which is expected to exhibit a quantum phase transition. The third magnetic system is consists of magnetic vortices in thin superconducting films containing ordered and disordered arrays of holes. The disordered system can be described by the random site, random field Ising model (RS/RFIM) in which particle interaction strength is controlled by simply changing the applied magnetic field. The critical properties of the spin systems will be probed via measurements of low temperature susceptibilities as a function of temperature and magnetic field. The local static configurations of the vortices in the superconductors will be examined using Bitter decoration, while the local dynamic motion of the vortices will be measured with Hall probe arrays. The educational component of this CAREER award will support development of an undergraduate research course, entitled "From the Minute to the Macroscopic: Probing the Properties of Atoms, Molecules, and Solids". The course will focus on experimental techniques in atomic and condensed matter physics, emphasizing the continuum in electronic and thermal properties from atoms to solids, and drawing on the research experience of the physics faculty at Wesleyan. %%% This is a CAREER award to a female scientist at a predominantly undergraduate institution. Physicists have been successful in developing a detailed understanding of electronic and magnetic properties in a wide range of materials. However, certain materials have not yielded to such an understanding owing to the presence of disorder and strong electronic interactions. A deeper understanding of such materials should aid in the development of advanced technological applications of these materials. This project will focus on the role of disorder and interparticle interactions in three magnetic systems. Two of these involve the magnetism produced by spins of electrons. The third is a system of magnetic flux tubes, called vortices, occurring in superconducting thin films with intentionally fabricated defects. The grant will also support the development of an undergraduate research course, entitled "From the Minute to the Macroscopic: Probing the Properties of Atoms, Molecules, and Solids". The course will focus on experimental techniques in atomic and condensed matter physics. It will emphasize the common physical concepts that are applicable from relatively simple atoms to complex solids. The course will draw on the research experience of the physics faculty at Wesleyan. The course will also be offered to high school teachers enrolled as summer students in the Graduate Liberal Studies Program at Wesleyan. This course will prepare both undergraduates and high school teachers to work in the research labs either during the school year or during a subsequent summer. ***
