9:30 AM - 11:30 AM
△ [6a-PB1-26] Synthesis and growth of Sr2Can-1CunOy superconductor grains using a high pressure synthesis method
Keywords:superconductor, high pressure synthesis method, single crystal
Some superconductive, cuptares, in the Sr-Ca-Cu-O system synthesized under high pressure were found to absorb water molecules and to improve Jc characteristics without changing the critical temperature. However the detailed crystal structure as not revealed yet. For that reason, preparation of Sr-Ca-Cu-O single crystals under high pressure have been awaited. In this study, single crystals of Sr2Can-1CunOy are grown under high pressure by a slow cooling method.
The precursors of SrCuO2, Ca2CuO3, CuO and SrO2 were mixed at a composition of Sr2CaCu2O6 in a glove box filled with Ar gas for 1 hour. The mixed powder was heated using a cubic anvil type press. under 5.5GPa. The synthesis temperature was kept at a temperature from 1000℃ to 1280℃ for 1 hour, then slowly cooled in from 0 hours to 15 hours and then depressurized. Growth of grains and characteristics of samples were investigated using a XRD, a digital microscope. The effects of the maximum temperature extracted from the temperature gradient on the grain size were investigated. Grains were extracted from the samples and the composition analysis was performed using SEM-EDS.
The growth of the grains and c-axis orientation were observed in the microscopic observations and XRD analyses when the slow cooling time was increased with changing the maximum temperature from 1000℃ to 1280℃. 1200℃was found to be the optimal temperature for the grains growth. In addition, when the temperature gradient was decreased, grains growth was observed.
Based on these, experiments, the optimum condition to grow grains was 1200-1150℃, cooled in 15hours and a pressure of 5.5GPa.The main phase was Sr2Ca2Cu3Oy from the XRD results.The major axis length was about 90μm. The EDS results imply that this grain was a Sr2CaCu2Oy crystal.
The precursors of SrCuO2, Ca2CuO3, CuO and SrO2 were mixed at a composition of Sr2CaCu2O6 in a glove box filled with Ar gas for 1 hour. The mixed powder was heated using a cubic anvil type press. under 5.5GPa. The synthesis temperature was kept at a temperature from 1000℃ to 1280℃ for 1 hour, then slowly cooled in from 0 hours to 15 hours and then depressurized. Growth of grains and characteristics of samples were investigated using a XRD, a digital microscope. The effects of the maximum temperature extracted from the temperature gradient on the grain size were investigated. Grains were extracted from the samples and the composition analysis was performed using SEM-EDS.
The growth of the grains and c-axis orientation were observed in the microscopic observations and XRD analyses when the slow cooling time was increased with changing the maximum temperature from 1000℃ to 1280℃. 1200℃was found to be the optimal temperature for the grains growth. In addition, when the temperature gradient was decreased, grains growth was observed.
Based on these, experiments, the optimum condition to grow grains was 1200-1150℃, cooled in 15hours and a pressure of 5.5GPa.The main phase was Sr2Ca2Cu3Oy from the XRD results.The major axis length was about 90μm. The EDS results imply that this grain was a Sr2CaCu2Oy crystal.