Abstract
In this paper we report the effect of Pr~6~O~11~ doping on the structural and superconducting properties of MgB~2~. The bulk samples of Pr~6~O~11~βdoped MgB~2~ have been prepared with nominal compositions Mg~1βx~(Pr~6~O~11~)~x/6~B~2~ (where xβ=β0.0, 0.01, 0.02, 0.03, 0.04, and 0.05) via a standard solidβstate reaction route by sintering in a reducing atmosphere of Ar/H~2~. The superconducting transition temperature T~c~ of MgB~2~ is found to decrease from 39 to 37βK when x increases from 0 to 0.05. The XRD results show the presence of MgO and PrB~6~ secondary phases in the doped samples besides the main hexagonal phase of MgB~2~. Improvement in critical current density (J~c~), irreversibility field (H~irr~), and upper critical field (H~c2~) of doped samples has been observed. The J~c~ values at 10 and 20βK of the xβ=β0.03 sample are higher in the entire field region (0β6βT). At 10βK and 2βT field the J~c~ values of undoped and 0.03 Pr~6~O~11~βdoped samples are 1.09βΓβ10^5^ and 2.21βΓβ10^5^βA/cm^2^, respectively. Variations of H~c2~, J~c~, H~irr~, and fluxβpinning force (F~p~) with doping concentrations have been studied in this paper and a correlation between these superconducting properties and structural characteristics of the samples has been found in the present work.