Critical Current and Pinning Features of a CaKFe4As4 Polycrystalline Sample

Armando Galluzzi; Antonio Leo; Andrea Masi; Francesca Varsano; Angela Nigro; Gaia Grimaldi; Massimiliano Polichetti

doi:10.3390/ma14216611

Critical Current and Pinning Features of a CaKFe₄As₄ Polycrystalline Sample

Materials (Basel). 2021 Nov 3;14(21):6611. doi: 10.3390/ma14216611.

Authors

Armando Galluzzi^{1

2}, Antonio Leo^{1

2}, Andrea Masi^{3

4}, Francesca Varsano³, Angela Nigro^{1

2}, Gaia Grimaldi², Massimiliano Polichetti^{1

2}

Affiliations

¹ Department of Physics "E.R. Caianiello", University of Salerno, Via Giovanni Paolo II 132, Fisciano, I-84084 Salerno, Italy.
² CNR-SPIN Salerno, Via Giovanni Paolo II 132, Fisciano, I-84084 Salerno, Italy.
³ ENEA, Via Anguillarese 301, I-00123 Roma, Italy.
⁴ Dipartimento di Ingegneria, Università degli Studi Roma Tre, Via Vito Volterra 62, I-00146 Roma, Italy.

Abstract

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.

Keywords: 1144 IBS family; DC magnetic properties; iron-based superconductors; magnetism and superconductivity; pinning force analysis; pinning properties.