Assistant professor Matthew C. Sullivan and Charlie Strehlow '09 presented their research at the annual meeting of the American Physical Society in New Orleans, Louisiana. This meeting was attended by over 7,000 physicists from all over the world.
Research Abstracts
"Demonstrating Levitation and Suspension of a Superconductor on a Magnetic Track": Charles P. Strehlow, M. C. Sullivan.
The suspension and levitation of superconductors by permanent magnets is one of the most fascinating consequences of superconductivity, and a wonderful instrument for generating interest in low-temperature physics. We present a novel classroom demonstration of the levitation/suspension of a superconductor over a magnetic track that maximizes levitation/suspension time, separation distance between the magnetic track, and superconductor as well as insulator aesthetics. A theoretical explanation of the levitation/suspension and a simple mathematical model of the lateral restoring forces are discussed.
"Doping Dependence of the Dynamic Critical Exponent in PCCO":
M. C. Sullivan, J. Sousa, M. Salvaggio, R. L. Greene.
Scaling analysis of voltage versus current isotherms is a favorite tool to study the normal-superconducting phase transition in cuprate superconductors. This measurement has never been performed on the electron-doped cuprate superconductor PCCO, despite unusual behaviors which may alter this phase transition and yield interesting results (behaviors such as the extended doping range of the anti-ferromagnetic phase and the quantum critical point). This is perhaps due to the lack of consensus regarding the analysis of voltage versus current isotherms, due in part to finite-thickness effects even in thick films. If finnite-thickness effects are taken into consideration, we can find the dynamic critical exponent z in our PCCO films. We present our results of the dynamic critical scaling exponent z as a function of doping.
