Department of Physics
Condensed Matter Seminar

In this talk, I will present two topics. For the first topic, we have investigated electron spin transport in nanometer scale aluminum grains as embedded in a ferromagnet tunneling junction. We observed tunnelling-magnetoresistance (TMR) and spin valve effects. TMR strongly exhibits asymmetry with bias voltage (behaviors like spin diodes). Additionally we obtained the spin-coherence time of order in nanoseconds by using the Hanle effect. For the second topic, we investigated the dielectric response of Ba₁-_xSr_xTiO₃ (BST) (a high dielectric ferroelectrics) nanoparticles. The results were unusually found to be Debye relaxation with only a single relaxation time for the dielectric response, and the relaxation time exhibits the Arrhenius law at temperatures below 200K.