To extend the model from Lectures 1 and 2 to include electron spin. Every electron is an elementary “magnet” with two states having opposite magnetic moments. Usually this has no major effect on device operation except to increase the conductance by a factor of two.
But it is now possible to inject, detect and manipulate spins in a controlled way and even use them to manipulate nanometer-sized magnets. The extended model will be used to describe such phenomena including spin-Hall effect, tunneling magnetoresistance (TMR) and spin-torque devices.
This lecture is part 1 of 2.