Structural and superconducting properties of bulk MgB2 with added nano Tb4O7

Abstract

Bulk MgB2 samples with 0, 1, 5 and 10 wt% of Tb4O7 nanoparticles added were prepared by a powder-in-sealed-tube (PIST) method. X-ray diffraction (XRD) analysis showed small quantities of TbB4, Tb2O3, Mg and MgO as impurities in the MgB2 matrix. No Tb4O7 is observed even for the 10 wt% addition. Scanning electron microscopy analysis showed a distinct microstructural change with the Tb4O7 addition. DC magnetization measurements showed a sharp superconducting transition in all the samples, without significant change in critical temperature (TC). The in-field critical current density (JC(H)) is improved for all the doped samples, and the JC(H) improvement in high fields is the highest for 10 wt% of Tb4O7 addition. The irreversibility field (Hirr) of the samples also improved with Tb4O7 addition. The improvement in JC(H) and Hirr of the added samples is due to the enhanced flux pinning consequent to the Tb4O7 addition.