The Depairing Current Density of a Fe(Se,Te) Crystal Evaluated in Presence of Demagnetizing Factors

The effect of the demagnetizing factor, regarding the determination of the de-pairing current density (Formula presented.), has been studied in the case of a Fe(Se,Te) crystal, using DC magnetic measurements as a function of a magnetic field (H) at different temperatures (T). First, the lower critical field (Formula presented.) (T) values were obtained, and the demagnetization effects acting on them were investigated after calculating the demagnetizing factor. The temperature behaviors of both the original (Formula presented.) values and the ones obtained after considering the demagnetization effects ((Formula presented.)) were analyzed, and the temperature dependence of the London penetration depth (Formula presented.) (T) was obtained in both cases. In particular, the (Formula presented.) (T) curves were fitted with a power law dependence, indicating the presence of low-energy quasiparticle excitations. Furthermore, by plotting (Formula presented.) as a function of T, we found that our sample behaves as a multigap superconductor, which is similar to other Fe-11 family iron-based compounds. After that, the coherence length (Formula presented.) values were extracted, starting with the (Formula presented.) (T) curve. The knowledge of (Formula presented.) and (Formula presented.) allowed us to determine the (Formula presented.) values and to observe how they are influenced by the demagnetizing factor.