adams@phys.lsu.edu (225) 578-6847
Miscellaneous Topics
Areas of Interest
For some years now we have been investigating a variety of model low dimensional systems that can provide insights into complex correlation effects that are known to be important in many condensed matter systems of current interest. In particular, we have investigated the quantum properties of helium films, non-degenerate electrons on cryogenic hydrogen surfaces, thin film BCS superconductivity in high magnetic fields, and the metal-insulator transition in ultra-thin homogeneously disordered "metal" films. In each of these areas the goal has been to isolate the salient characteristics of what is an ostensibly well-controlled system with the ultimate goal of gaining a deeper understanding of quantum correlation effects in more widely studied materials.
Current Project
We are studying the interface-mediated exchange field induced in Al films that are deposited on the ferromagnetic insulator EuS, see left figure. Much of the work in the last 10 years on superconducting-ferromagnetic bilayers has been focused on the superconducting order parameter that is induced in the FM side of the interface. We, however, are interested in the nature of the exchange field that is concurrently induced on the SC side. Our spin-resolved tunneling measurements conclusively show that the exchange field in the Al is a non-linear function of the external applied field. The origin of this unexpected field dependence is unknown. The fact that the exchange field is not static opens up the possibility that an external parameter, such as a gate voltage, could be used to control its strength. This could, of course, then be exploited form the basis of a device such a superconducting switch.(read more...)