Publication Type
Journal
Journal Name
Physical Review B
Publication Date
Page Number
224523
Volume
79
Issue
22
Abstract
We report the basal-plane superfluid density and critical current of magnetically aligned NdFeAsO<sub>0.86</sub>F<sub>0.14</sub> powder. This sample has individual crystallite grains permanently oriented with their <i>c</i> axis along the external field. The small particles provide a sensitive indicator of <i>dc</i> flux penetration, and allow analysis of the temperature dependence that suggests two-gap characteristics. A quantitative determination of the absolute magnitude is hindered by the need for accurate knowledge of the particle size distribution. 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.
