Patent ID: 8476900

Claim:
A system for use in detecting an electromagnetic wave, comprising: a device comprising: a first magnetic layer having a fixed magnetization direction; a second magnetic layer having an unfixed magnetization direction responsive to the electromagnetic wave; and a barrier layer positioned between the first and second magnetic layers; wherein the device has an impedance dependent on a relative angle between the fixed magnetization direction and the unfixed magnetization direction, the relative angle initially configured to be one of approximately 0 degrees and 180 degrees; an external magnetic field source configured to apply an external DC magnetic field to the device, the external magnetic field source configured to sweep the external DC magnetic field to cause the relative angle to switch from the one of approximately 0 degrees and approximately 180 degrees to the other one of approximately 0 degrees and approximately 180 degrees; and a detector configured to measure a change in voltage across the device adjacent a switching region of the relative angle, the change in voltage indicative of the electromagnetic wave.