The magnetization of PrFeAsO0.60F0.12 superconductor

The magnetization of the PrFeAsO0.60F0.12 polycrystalline sample has been measured as functions of temperature and magnetic field (H). The observed total magnetization is the sum of a superconducting irreversible magnetization and a paramagnetic magnetization. Analysis of dc susceptibility χ(T) in the normal state shows that the paramagnetic component of magnetization comes from the Pr3+ magnetic moments. The intragrain critical current density (JL) derived from the magnetization data is large. The JL(H) curve displays a second peak which shifts towards the high-field region with decreasing temperature. In the low-field region, a plateau up to a field H* followed by a power law H−5/8 behavior of JL(H) is the characteristic of the strong pinning. A vortex phase diagram for the present superconductor has been obtained from the magnetization and resistivity data.

Research highlights
► The critical current density JL exhibits a second peak well below Hc2(T).
► A plateau up to H* followed by H−5/8 behavior of JL(H) is the characteristic of strong pinning.
► The pinning force and the density of pinning centers increase with oxygen vacancies.
► PrFeAsO0.60F0.12 displays a rich vortex phase diagram.