Forming the Fe(Se$_{1-x}$Te$_{x}$) superconducting coatings on the iron surface

To obtain superconducting coatings Fe(Se$_{1-x}$Te$_{x}$) on the surface of iron substrates (strip, tape) two techniques have been used: deposition of coatings from chalcogen vapor and deposition of coatings from a melt of chalcogenides. The resulting coatings had a $\beta$-phase structure of the FeSe compound and critical superconductivity parameters close to those of bulk polycrystals. It was shown that for deposition of coatings is mandatory to use compositions including Se and Te, and the optimal substrate is pure iron. The critical current density of coatings were estimated using the magnetic moments dependences on the magnetic field. At $T$ = 4 K and fields greater than 4 T, the critical currents were of the order of 10$^3$ A/cm$^2$ for both types of coatings and change slightly with increasing magnetic field.