| Title |
Characterization of YBa_2Cu_3O_{7-x}F_y Superconducting Materials Made by a Sol-Gel Process |
| Keywords |
졸-겔 법으로 YBa_2Cu_3O_{7-x}F_y에 불소첨가 ; 고체 ^{19}F핵자기공명 Fluorination of YBa_2Cu_3O_{7-x}F_y by a sol-gel process ; Solid-state ^{19}F NMR |
| Abstract |
Fluorine-doped YBaS12TCuS13TOS17-xTFS1yT superconducting materials with y varing two orders of magnitude form 0.02 to 2.0 have been prepared by a sol-gel process by using metal nitrate salts, sodium hydroxide and sodium fluoride. Fluorine contents have been measured using an ion-selective electrode. All fluorine doped as reactant were found to be present in the resulted samples. From the observation of XRD it has been concluded that the samples with y 0.2 formed simply the single phase of perovskite structure, whereas those with y 0.5 yielded together some compounds such as BaFS12T, YFS13T and CuO in the resulted samples. The observation of solid state S019TF NMR has been carried out in order to check whether fluorine was actually incorporated into the lattice sites, and the experimental results revealed that the mole ratio of fluorine incorporated into the lattice sites of YBaS12TCuS13TOS17-xT was approximately 0.2 per mole of the compound. Also electrical resistivity measurement indicated that onset transition temperature has the tendency to increase slightly with increasing y in the dilute region as y 0.2. |