Giant Magnetoresistance in Boundary-Driven Spin Chains

In solid state physics, giant magnetoresistance is the large change in electrical resistance due to an external magnetic field. Here we show that giant magnetoresistance is possible in a spin chain composed of weakly interacting layers of strongly coupled spins. This is found for all system sizes even down to a minimal system of four spins. The mechanism driving the effect is a mismatch in the energy spectrum resulting in spin excitations being reflected at the boundaries between layers. This mismatch, and thus the current, can be controlled by external magnetic fields resulting in giant magnetoresistance. A simple rule for determining the behavior of the spin transport under the influence of a magnetic field is presented based on the energy levels of the strongly coupled spins.

Automated summary

Giant magnetoresistance has been observed in a spin chain composed of weakly interacting layers of strongly coupled spins, even in systems as small as four spins. The effect is driven by a mismatch in the energy spectrum leading to spin excitations being reflected at layer boundaries, which can be controlled by external magnetic fields to achieve giant magnetoresistance. A simple rule based on the energy levels of the strongly coupled spins can predict the behavior of spin transport under the influence of a magnetic field.