Fabrication of the Co and Mo-substituted MgB2 tapes using PIT (powder-in-tube) method and their general characterization

ABSTRACTM.Sc.ThesisFABRICATION OF THE Co AND Mo-SUBSTITUTED MGB2 TAPES USING PIT(Powder-In-Tube) METHOD AND THEIR GENERAL CHARACTERIZATIONEmine BAYAZİTInonu UniversityGraduate School of Natural and Applied SciencesDepartment of Physics77 + ix pages2005Supervisor: Prof. Dr. M. Eyyüphan YAKINCIIn this study, tapes with nominal compositions of (MgB2)1-xAx (A=Co (0.005≤x≤0.5),Mo (x=0.005≤x≤0.3)) were prepared by using Powder-In-Tube (PIT) method. The effects ofthe magnetic substitutions on the superconducting properties were investigated usingstructural, electrical and magnetisation measurements.The results obtained revealed that the superconductivity was destroyed with themagnetic substitutions. A dominant ferromagnetic phase was observed for high Co-substitution. It was observed that the growth of the impurity phases in the grain interfaces ofthe main matrix and the formation of weak coupling between the grains plays an importantcrucial role on the electrical conducting paths of the system for both substitution cases.Considering the results obtained in this work, it was concluded that the magneticsubstitutions are not suitable for the MgB2 superconducting system.Keywords: Superconductivity, PIT method, diamagnetism, ferromagnetism, critical currentdensity.