Doping effects of Nd₂O₃ on the superconducting properties of powder-in-tube MgB₂ tapes

Nd₂O₃ doped Fe-sheathed MgB₂ tapes with different doping levels were fabricated by the insitu powder-in-tube method, and their superconducting properties were studied systematically. The x-ray diffraction (XRD) patterns showed the main phase of MgB₂ along with the impurity phases such as MgO and NdB₆ in the Nd₂O ₃ doped samples. Compared to the undoped tapes, the critical current density J_c of all the doped samples was improved with only a slight suppression of the critical temperature T_c, and the 5at.% Nd ₂O₃ doped tapes achieved the highest J_c. Through the transmission electron microscope (TEM) study, nanoscale impurity particles were found in the 5at.% Nd₂O₃ doped samples, and they were thought to be responsible for the enhanced pinning behavior and thus the increased critical current density.