Properties of YBCO superconductors prepared by ammonium nitrate melt and solid-state reaction methods

Abstract

Ceramic YBCO superconductors were prepared by: (1) ammonium nitrate melt, (2) solid-state reaction methods and the properties of the samples obtained were compared. Under the same annealing conditions single phase YBCO was synthesized at a lower temperature by the former method. Moreover, at 900 °C Y-123 phase and the initially adjusted Y-211 additive could be formed using ammonium nitrate melt, but not with the solid-state method which leads Y-123 at a higher temperature (950 °C) without Y-211 additive. The samples prepared with ammonium nitrate melt technique have smaller grains, more grain boundaries and weak links causing low J c and wide superconducting transition temperature. Superconductors produced by this technique may be suitable for applications like magnetic field sensors that require small grains and reversible magnetization.