Overview
Spintronic diodes allow the current to flow in only one direction. Each diode only turns clockwise, but it can be used to allow counterclockwise current by placing it on the outside of a chain loop.
Detailed description
The ratchet mechanism on top allows only clockwise movement and requires a forward voltage of approximately 0.7 V. The reverse breakdown voltage is well above the rated maximum voltage of the chain.
Note that only one spintronic diode is required to build a half-wave rectifier and only two are necessary to build a full-wave rectifier.