The magnetization of PrFeAsO${}_{0.60}$F$_{0.12} sueprconductor

Abstract

The magnetization of the PrFeAsO${}_{0.60}$F${}_{0.12}$ 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 ($M_s$) and a paramagnetic magnetization ($M_p$). Analysis of dc susceptibility $\ddot{I}‡(T)$ in the normal state shows that the paramagnetic component of magnetization comes from the Pr${}^{+3}$ magnetic moments. The intragrain critical current density $(J_L)$ derived from the magnetization measurement is large. The $J_L(H)$ 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 $H^{\ast }$ followed by a power law $H^{-5/8}$ behavior of $J_L(H)$ is the characteristic of the strong pinning. A vortex phase diagram for the present superconductor has been obtained from the magnetization and resistivity data.

A revised version with modified title,8 pages, 7 figures