Aligned crystallite powder of NdFeAsO0.86F0.14: Magnetic hysteresis and penetration depth

作者：Zuev Yuri L^*; Specht Eliot D; Cantoni Claudia; Christen David K; Thompson James R; Jin Rongying; Sefat Athena S; Mandrus David G; McGuire Michael A; Sales Brian C

来源：Physical Review B, 2009, 79(22): 224523.

DOI：10.1103/PhysRevB.79.224523

• arsenic compounds
• critical current density (superconductivity)
• crystallites
• flux pinning
• high-temperature superconductors
• iron compounds
• magnetic hysteresis
• neodymium compounds
• particle size
• penetration depth (superconductivity)

We report the basal-plane critical current and superfluid density of magnetically aligned NdFeAsO0.86F0.14 powder. This sample has individual crystallite grains permanently oriented with their c axis along the external measuring field. Magnetic irreversibilities at high field suggest strong flux pinning of basal-plane critical currents, with monotonic field dependence and no evidence of the "fishtail" effect. The small particles provide a sensitive indicator of dc flux penetration and allow analysis of the temperature dependence of ab-plane London penetration depth lambda(ab,L), which is quadratic at low T. This feature may not necessarily be due to the nodes in the gap but may be rather a sign of a strong pair breaking. A quantitative determination of the absolute magnitude of lambda(ab,L) is hindered by the need for accurate knowledge of the particle size distribution.

• 出版日期2009-6