Precipitation of superconducting, single phase EuBa2Cu4O8 from molten hydroxide at 475 °C

A solution route involving reactive precipitation from molten hydroxide melts is presented for the synthesis of EuBa2Cu4O8. The melt consisted of a mixture of NaOH, KOH, and Ba(OH)2, and was heated at 475 °C for ∼2 h prior to reactant addition. Eu2O3 and CuO were then added, and in several hours crystallites of EuBa2Cu4O8 were obtained. The product was a single phase as determined by powder x‐ray diffraction and the onset of superconductivity was observed at 78 K by dc magnetic susceptibility.