Growth and Microwave Properties of FeSe Thin Films and Comparison With Fe(Se,Te)

In this work, we have grown ∼100 nm thick pristine FeSe films by pulsed laser deposition. The films were structurally characterized with X-ray diffraction and their surface morphology checked through atomic force microscopy. Microwave measurements, performed with a dielectric loaded resonator tuned at the frequency of 8GHz, allowed the characterization of the samples surface resistance, in view of potential applications in microwave haloscopes for dark matter search. Here, we report the comparison of the microwave properties of FeSe with Fe(Se,Te) thin films, as the temperature is swept from 4 K to 20K. By applying a constant static magnetic field of 12T, it was also possible to discern the magnetic field resilience of the two samples. FeSe showed a larger critical temperature drift as the field is applied and a small broadening, while the opposite appears in Fe(Se,Te). A preliminary analysis of vortex pinning shows margins for optimizing pinning in FeSe.