High pressure and hot-pressing manufactured magnesium diboride. Inclusions of higher borides as possible pinning centers in the material
- T. Prikhna, W. Gawalek, Y. Savchuk
- Journal of Optoelectronics and Advanced Materials…
Critical current density of high-pressure (2 GPa) manufactured -based superconductors depends on the amount and distribution of higher borides in matrix, which in turn are determined by the nature of the initial components first of all B or and the temperature of sintering or synthesis. Ti and Ta additions can improve by promoting the higher boride formation via impurity hydrogen absorption, thus preventing detrimental for being formed, which possibly increases the nucleation barrier. SiC (0.2–0.8 ) addition increases of , allowing us to get at 20 K in the 1 T field: pinning is increased by SiC and higher boride grains and there is no notable interaction between SiC and . As the synthesis temperature increases from 800 to 1050 , Ti and SiC additions may affect the oxygen segregation and formation of Mg-B-O inclusions enriched with oxygen as compared to the amount of oxygen in the matrix, which can also promote an increase in pinning. Materials high-pressure synthesized from Mg and B taken in 1:4, 1:6, 1:7, 1:8, 1:10, 1:12, 1:20 ratios were superconductive with of about 37 K. High ( in zero field at 10–30 K, respectively) showed materials with the matrix composition near stoichiometry, they have doubled microhardness of .