Analysis of peak effect in the critical current density and flux pinning properties in iron based superconducting Ca₁₀(Pt₄As ₈)(Fe_2-xPt_xAs₂)₅ single crystal

We present the magnetic properties of the iron based superconducting Ca₁₀(Pt₄As₈)(Fe_2-xPt _xAs₂)₅ (x =0.01) single crystal as a function of field and time. The single crystals were grown by Bridgman method and showed T_c of 32 K. The results show that the well-known secondary peak effect becomes prominent in certain temperature range in the field dependent magnetic hysteresis. Moreover, the maximum of pinning force density F _max versus H_max follows a scaling law F_p,max 49.5H_max^3/2 indicating the single type pinning mechanism is involved in the sample within our measured temperature range. The time dependence of the magnetization indicates thermally activated flux motion and the relaxation rate reveals a plateau in the temperature region where secondary peak effect is more prominent after that a sudden increase is observed. We found that the magnetization dependence of activation energy U obtained by Maley's method follows a power law in low temperature region with exponent μ 0.15 which is in good agreement with collective pinning theory.