Critical Current and Pinning Features of a CaKFe₄As₄ Polycrystalline Sample

We analyze the magnetic behavior of a CaKFe4As4 polycrystalline sample fabricated by a mechanochemically assisted synthesis route. By means of DC magnetization (M) measurements as a function of the temperature (T) and DC magnetic field (H) we study its critical parameters and pinning features. The critical temperature T_c has been evaluated by M(T) curves performed in Zero Field Cooling-Field Cooling conditions. These curves show the presence of a little magnetic background for temperatures above T_c, as also confirmed by the hysteresis loops M(H). Starting from the M(H) curves, the critical current density J_c of the sample has been calculated as a function of the field at different temperatures in the framework of the Bean critical state model. The J_c(H) values are in line with the ones reported in the literature for this typology of samples. By analyzing the temperature dependence of the critical current density J_c(T) at different magnetic fields, it has been found that the sample is characterized by a strong type pinning regime. This sample peculiarity can open perspectives for future improvement in the fabrication of this material.