Pinning properties of Ag/MgB 2 bulk system

Abstract

Bulk MgB 2 containing nano-particles of Ag–Mg alloys were sintered from the mixtures of Mg-, B- and Ag 2O-powder with the mole ratio of Mg:B:Ag 2O = 1.6 (1− x):2(1− x): x/2, where x was the nominal concentration of Ag from 0 to 0.1. The solid reaction of the powder mixture was performed in the electric furnace at 900 °C for 30 min under Ar-atmosphere with 10% H 2 gas. The X-ray diffraction patterns and images of transmission electron microscope showed the production of Ag–Mg nano-particles in bulk MgB 2, except for MgO impurity. For x = 0.01 and 0.02 samples, the enhancement of J c was observed without T c reduction, which means the efficiency of the nano-particles of Ag–Mg as the pinning centers in MgB 2.