Synthesis and characterizations of YBa2Cu3O7-5 superconductor with added AI2O3 nanoparticles via citrate-nitrate auto-combustion reaction / Mohd Shahadan Mohd Suan

Superconductor materials are renowned to conduct electricity at zero resistance and capable to expel magnetic flux. It can be used in developing efficient wire cables, magnetic energy storage and levitation technologies. Thus, the high temperature superconductor YBa2Cu3O7-δ with added Al2O3 nanoparticles was synthesized via citrate-nitrate auto-combustion reaction process. The novelty of this research work is the citrate-nitrate auto-combustion reaction method consumed less energy and time compared with other conventional synthesis methods for processing of composite superconductor oxides and produced well distribution of Al2O3 nanoparticles in YBa2Cu3O7-δ superconductor. The auto-combustion reaction transformed the formulated precursor citrate-nitrate gel into very fine ashes. It yielded Al2O3 and YBa2Cu3O7-δ phases after calcination process which was further heat treated to achieve superconductivity. The reactions during synthesis processes were investigated through the thermal evaluations. The effects of different concentration of Al2O3 nanoparticles on the structure, superconducting, magnetic and mechanical properties of YBa2Cu3O7-δ were investigated and appraised. The sustained orthorhombic structure in each sample contributed to consistency in superconducting transition temperature while the flux pinning forces provided by the non-superconducting nanoparticles improved the critical current density. Furthermore, the mechanical hardness of the samples was also influenced by the addition of nanoparticles. This work shows that the citrate-nitrate auto-combustion reaction is an effective method to introduce Al2O3 as nanoparticles homogeneously distributed in the YBa2Cu3O7-δ superconductor