Anisotropic Effect of Proton Irradiation on Pinning Properties of Fe(Se,Te) Thin Films

At the present day, iron-based superconductors (IBS) can he considered as competitors of cuprates for the fabrication of superconducting cables for high field application in the presence of particle irradiation. In particular, it has been demonstrated that 11-IBS are very robust against proton irradiation. In this paper, we analyze the effect of this kind of irradiation on the anisotropy of superconducting and pinning properties of Fe(Se,Te) thin films grown on CaF2. By electrical transport measurements, we evaluate the upper critical field as a function of the temperature and the pinning activation energy as function of the applied magnetic field, for different orientation between the material crystal structure and the field itself, in pristine and irradiated samples. The aim is to recognize if and how proton irradiation modifies the anisotropy of the material properties.