Spinodal decomposition of the nonstoichiometric YBa2Cu3O7−δ compound at room temperature

Electron and polarized-light optical microscopy have been used to study the spinodal decomposition of the YBa2Cu3O7−δ compound depending on the oxygen content. Experimental data reported indicate that whatever the state —initial or preliminarily aged at a high temperature—of the YBa2Cu3O7−δ (δ ≈ 0.2 and 0.4) nonstoichiometric oxide, it undergoes natural aging typical of metallic alloys.