Fig. 2
From: Unique defect structure and advantageous vortex pinning properties in superconducting CaKFe4As4
Critical current properties of CaK1144 single crystal for H // c. a MHLs at T = 3–20 K. b MHLs at T = 3 and 20–32 K. c Magnetic field dependence of Jc. d Temperature dependence of Jc at μ0H = 0.4, 1, 3 and 6 T. e Comparison of Jc with representative 122 single crystals27, BaK122 (red), Co-Ba122 (blue), and P-Ba122 (green) with various doping concentrations x. In addition to CaK1144, P-Ba122 with x = 0.38 shows an increase in Jc with increasing T. In this case, however, a MHL is characterized by a sharp second magnetization peak, which is apparently different from CaK114427
