Influence of oxygen doping on critical fields in MgB2 bulk superconductors

[摘要] In this work we studied the influence of SnO2doping on the critical fields and temperatures of MgB2bulk samples. Bulk samples were made by mixing ex-situ MgB2powder with 5 wt% SnO2powder and then pressing the mixed powders into pellets using a pressure of 2000 psi. The bulk pellets were sintered at 900°C in a furnace under flowing Ar. The samples were quenched to room temperature after dwelling at 900°C for 5h. XRD, SEM, and magnetic measurements were made on doped and control samples. XRD showed a decomposition of the SnO2and very slight reductions in the a-axis and c-axis lattice parameters of the MgB2phase. M-T (Magnetization-Temperature) curves showed a decrease in Bc2of approximately 1 T in the temperature range of 24 K - 39 K with SnO2additions as compared to the control samples.

[发布机构] Center for Superconducting and Magnetic Materials, Department of Materials Science and Engineering, Ohio State University, Columbus; OH; 43210, United States^1;Hyper Tech Research Incorporated, Columbus; OH; 43212, United States^2

[关键词] Bulk samples;Control samples;Critical fields;Influence of oxygen;Magnetization temperature;MgB2 powders;Mixed powder;Temperature range