Structural and superconducting properties of tungsten and iridium films for low-temperature microcalorimeters

The deposition technology and the basic properties of thin layers of tungsten and iridium, promising for the creation of superconducting low-temperature microcalorimeters in the temperature range from 15 to 100 mK, are investigated. Superconducting layers of the $\alpha$-phase of tungsten with a low superconducting transition temperature $T_c$ $\sim$ 15 mK and superconducting iridium layers with $T_c$ $\sim$170 mK have been obtained, which can serve as the basis for the formation of bilayers with a superconducting transition temperature in the range 15–100 mK.