838C Student Seminar

Physics 838 Seminar
09.25.2017 4:00 pm - 5:00 pm


Speaker: Christos Tengeris (Appelbaum)

Title: Origins of magnetic field-dependent open-circuit voltage hysteresis driven by transverse charge current in ferromagnet/normal metal structures

Abstract: Using open-circuit voltage measurements between a thin ferromagnetic film and a thin Au film in contact we observe a magnetic field-dependent hysteresis of this voltage when a charge current is driven through the Au channel and transverse to the externally applied magnetic field. This signal is very similar both qualitatively and quantitatively to the one observed in devices of similar geometry but with a topological insulator in the conducting channel. This voltage hysteresis indicates the presence of a non-equilibrium ensemble spin polarization at the interface between Au and the FM layer. In this experiment, we study the effects that various parameters (such as the current density, thin film thickness, and temperature) have on the magnitude and the sign of this spin polarization signal and we attempt to resolve the different origins that contribute to this phenomenon.

I-Lin Liu (Butch/Paglione)