Influence of magnetism on the superconducting properties of iron-based superconductor NdFeAsO0.88F0.12

TL;DR

This study investigates how magnetism influences the superconducting properties of NdFeAsO0.88F0.12, revealing magnetic effects on susceptibility, hysteresis, and flux pinning, with implications for understanding magnetic interactions in iron-based superconductors.

Contribution

It provides new insights into the magnetic background effects and their impact on superconductivity in NdFeAsO0.88F0.12, including the role of spin-glass behavior.

Findings

Magnetic susceptibility crossover observed under 7.5KOe.

Paramagnetism of Nd3+ ions affects hysteresis loops.

Magnetic background attributed to spin-glass state does not impair flux pinning.

Abstract

Both DC and AC magnetization measurements were performed on the NdFeAsO0.88F0.12 superconductor to investigate the influence of magnetism on the superconducting properties of this system. The crossover of the ZFC and FC magnetic susceptibility curves under 7.5KOe was observed. The imaginary component of the first harmonics of the AC magnetic susceptibility, increases with the increasing DC field below 10K and shows frequency dependency under 7.5KOe at low temperature. The paramagnetism of Nd3+ ions tilts the magnetic hysteresis loops and broadens the hysteresis width. After correction for the paramagnetism, the field and temperature dependence of intrinsic Jcm was obtained and compared with the experimentally obtained total Jcm. The origin of the abnormal behavior of magnetization was investigated and attributed to a magnetic background, which was speculated to be caused by the spin-glass state. However, this magnetic background does not affect the flux pinning properties in this sample. The related mechanism was discussed.