Conductance quantization and magnetoresistance in magnetic point contacts

We theoretically study the electron transport through a magnetic point cont act (PC) with special at tention given to the effect of an atomic scale dom ain wall (DW). The spin precession of a conduction electron is forbidden in such an atomic scale DW and the sequence of quantized conductances depends on the relative orientation of magnetizations between left and right elect rodes. The magnetoresistance is strongly enhanced for the narrow PC and osc illates with the conductance.