Preparation and Formation Process of TlBa2Can-1CunOy

Abstract

The Tl–Ba–Ca–Cu–O compounds, TlBa₂Ca _n-1Cu _n O _y (n = 1–5), with a single Tl–O layer and multiple Cu–O layers per unit cell were prepared. The formation process of these phases was studied. The numbers of Cu–O and Tl–O layers were influenced by the thallium content. Control of the thallium content was essential to prepare the desired phases in the Tl–Ba–Ca–Cu–O system. The value of T _c increased with increasing number of Cu–O layers (1≤n ≤4). At n=5 T _c was lower than that at n =4. Therefore, the highest T _c value was obtained at n=4.