[4] A multilayer of conductor and magnetic material is needed to construct a device that exhibits the spin Hall magnetoresistance.
As most spin diffusion lengths are short, the effect is only significant in materials that are only several nanometers thick.
One of the signatures of the spin Hall magnetoresistance is that the change in resistance is observed when the magnetization of the insulator is rotated with respect to the spin axis and not to the direction of the charge current as is seen in anisotropic magnetoresistance.
[1] In platinum, the maximum resistance change is found to reach a maximum at approximately 120K for all thicknesses[6] Due to the spin-transfer torque at the interface of the conductor and magnet, a spin current can be injected from the metal into the insulator.
This allows for new spintronics experiments to investigate the possibility of transmitting spin information through an insulator which would have the advantage of no power loss due to Joule heating.