Abstract
Bi2Sr2CaCu2O8+δ(2:2:1:2) single crystals are in-situ heated in a transmission electron microscope in order to investigate the structure evolution of thin foils in the vacuum. The structure becomes unstable at about 250°C, and strain fields are produced along the a and b directions by the thermal expansion of the lattice; tweed contrast is formed and at about 300°C twin-like deformations or precipitations occur owing to the local monoclinic lattice disorder. The deformed areas extend in the temperature range from 300 to 400°C. From 400 to 450°C a new superstructure is induced presumably by the loss of oxygen or by a change of the oxygen configuration. Serious structure distortions above 400°C make the lattice decompose locally. Above 460°C, the 2:2:1:2 structure completely decomposes.