A Research On Spintronics And The Spin-rectification-based Photo-detection Technique

When compared with the success of semiconductor-based photo-detectors in thesensing, where the electrons/holes absorb/radiate the energy of photons and convert itinto a photo-voltage/conductivity output through the transition between the energybands/sub-bands, the development of microwave detection in the literature keeps theprinciple from the classical electrodynamics, and is mainly based on the RF electricalcircuit which is sensitive to its parasitic transmitting background. In this dissertation,an on-chip photo-detection technique for microwave is proposed and discussed, whichis physically based on and inspired by the spin rectification effect in the ferromagneticmaterial. Here in the view point of quantum mechanics, the states transition of spin inthe material between the orientations parallel and anti-parallel to the applied externalmagnetic field has the eigen energy in the same order with the photon of microwave,which introduces the solid state sensor to the group ranging from visible/infrared lightto microwave.The physical fundamental of the microwave detection here is the spin rectificationeffect, which is generated from the coherently coupling of dynamic resistance of theferromagnetic material driven by the magnetic component of the microwave and theac current in the material driven by the electrical component. This leads to a rectifieddc voltage output in the sensor from the high frequency EM wave with highmagnitude and phase sensitivity.A spintronic Michelson Interferometer, which contains the microwave sensormentioned above, is used to set up the near-field microwave imaging system, and thedielectric constant of ideal/strong-absorption dielectric is measured, as well as thesub-wavelength structure being imaged for both dielectric and metal.