Doping effect of nano-Ho2O3 and naphthalene in MgB2 superconductor prepared by powder-in-sealed-tube method

作者：Hansdah J S; Sarun P M^*

来源：Journal of Applied Physics, 2015, 117(11): 113903.

DOI：10.1063/1.4915348

The effect on crystal structure, critical temperature (T-C), and critical current density (J(C)) of bulk MgB2 doped with nano-Ho2O3 and naphthalene was studied. Among all the samples studied, the sample doped with 2.5wt. % nano-Ho2O3 have shown the best field dependent critical current density [J(C)(H)], i.e., 0.77 x 10(5) A/cm(2) at 2 T and 10K. While naphthalene doped MgB2 sample has shown the least J(C)(H) characteristics. The improved J(C)(H) characteristics in the nano-Ho2O3 doped MgB2 samples are attributed to improved flux pinning properties due to the formation of HoB4 and in naphthalene doped MgB2 samples. The slight lower T-C value (37.01 K) in naphthalene doped samples is attributed to the occurrence of lattice defect by the substitution of carbon at boron site of MgB2 superconductor. Lower Delta T-C value implies the lesser anisotropy in all the synthesized samples. The flux pinning force density (F-P/F-Pmax) curves are theoretically analyzed using Dew-Hughes model. The result revealed that point pinning is the dominant pinning mechanism for nano-Ho2O3 doped MgB2 samples, while, surface and grain boundary pinning become dominant with increasing naphthalene addition in nano-Ho2O3 doped MgB2 samples.

• 出版日期2015-3-21