Synthesis Of MgB₂ Bulks By Powder-in-tube Method And Research To Improve Jc

In 2001 the discovery of MgB₂ superconductivity excites people in the condensed matter realm and arouses the upsurge of the study in high critical temperature superconductor. MgB₂ is a new material with superconductivity, it builds a new way for us to study those high-temperature superconductors (HTSC) with simple composition, it will be a rising new star in the electronic material field. The new material is better than HTSC in many ways, such as little anisotropy, large interfere length and non-weak link phenomenon. All of these advantages make MgB₂ have a good applying prospect. But as a new superconductor, it has many unknown characters to be studied.We have made MgB₂ bulks by PIT method (power-in-tube). we got the best parameter for this method by chang the temperature, time, etc.The bulks we made have a bigger density than other methods without pressing when reaction. At last,we compared the Tc,Jc and other charaters of with the bulks made in different temperature or different reaction time.On the base of the method mentioned above, we changed the temperature's increasing rate(726℃/min) to make MgB₂ bulks. Contrast to the common temperature's increase rate(10℃/min) . We can let reaction accomplish quickly. In this method, we also made MgB₂ bulks with higher Jc than the bulks made by the common temperature's increase rate.Dense polycrystalline MgB₂ bulk samples doped with SiC were prepared by powder-in-tube (PIT) process. M-H loops were measured at different temperatures and the magnetic critical current density Jcm was obtained using Bean model. The Jcm changes with the content of SiC and the best content is determined according to Jcm. An increase of Jcm is observed on samples doped with proper SiC content, especially at higher magnetic fields. Magnetization relaxation was measured to investigate this phenomenon.