Investigations of the transmission and reflection spectra of THz radiation of magnetic metallic nanowires

The transmission and reflection spectra of arrays of heterogeneous nanowires made of Ni/Co, FeNi/Co, and Ni/Fe, formed in track polymer membranes by the galvanic method, have been studied in the frequency range from 16 to 250 THz. Many peaks in the 16-20 THz range were found in the transmission spectra, while they are not observed in the spectrum of a track membrane without nanowires. The absorption spectra of an array of nanowires in a track membrane and a membrane without wires are calculated from the obtained spectra. It was found that the fraction of the THz radiation power absorbed by nanowires and its spectrum depend on the materials of the nanowires. The features of the observed spectra can be explained by two mechanisms. The first is the inverse laser effect in magnetic nanocontacts. And the second is the change in electrical resistance due to spin-flip transitions between the spin subbands in the case of a non-coplanar distribution of the magnetization of the magnetic layers. This class of quasi-one-dimensional structures looks promising for creating THz radiation detectors in a wide spectral range and at room temperature.