Magnetization and characteristic fields in Nd0.8Ba0.2FeAsO0.6F0.4 with binary doping

In the present work, the iron oxypnictide superconductor of the namely Nd0.8Ba0.2FeAsO0.6F0.4 is prepared with respect to the observation of distinct magnetization characteristics arising from both electron and hole doping. A magnetothermal phase diagram is given for the present iron oxypnictide system, based on the irreversibility fields (HirrHirr) and the upper critical fields (Hc2Hc2) obtained from magnetotransport measurements, as well as the lower critical fields (Hc1Hc1) evaluated by magnetization loops at various temperatures. High Hc2(0)Hc2(0) are revealed at low temperature range, which is in consistent with the observations of comparatively high critical current (JcJc) and the temperature dependent peak effect in the JcJc vs HH curves.

► The 1111 type iron oxypnictide superconductor with binary doping. ► The namely Nd0.8Ba0.2FeAsO0.6F0.4 with both electron and hole doping. ► A high Hc2(0)Hc2(0) of about 163 T, estimated by both GL theory and WHH formula. ► A large slope of dHc2(T)/dT|Tc implying more breaking of original symmetry. ► High JcJc and associated peak effects suggesting the flux pinning.