Thermoelectric Radiation Detector Based on Superconductor-Ferromagnet Systems

We suggest an ultrasensitive detector of electromagnetic fields exploiting the giant thermoelectric effect recently found in superconductor-ferromagnet hybrid structures. Compared with other types of superconducting detectors where the detected signal is based on variations of the detector impedance, the thermoelectric detector has the advantage of requiring no external driving fields. This is especially relevant in multipixel detectors, where the number of bias lines and the heating induced by them are an issue. We propose different material combinations to implement the detector and provide a detailed analysis of its sensitivity and speed. In particular, we perform a proper noise analysis that includes the cross correlation between heat and charge current noise and thereby describes also thermoelectric detectors with a large thermoelectric figure of merit.