Jessica Gifford

Continuous control of spin polarization using a magnetic field

The giant magnetoresistance (GMR) of a point contact between a Co/Cu multilayer and a superconductor tip varies for different bias voltage. Direct measurement of spin polarization by Andreev reflection spectroscopy reveals that the GMR change is due to a change in spin polarization. This work demonstrates that the GMR structure can be utilized as a spin source and that the spin polarization can be continuously controlled by using an external magnetic field.

Singlet superconductivity in SmO 0.82 F 0.18 FeAs

In this paper, the Andreev reflection method which employs magnetic materials with various spin polarization has been used to study the superconductivity of SmO0.82F0.18FeAs. It is shown that this method can be utilized to measure the spin of Cooper pairs if a highly spin polarized current is used.