Temperature and X-Ray illumination effects in oxygen doped La2CuO4

We have investigated charge ordering in an oxygen doped La2CuO4,1 crystal by high resolution x-ray diffraction using synchrotron radiation. Thanks to the high brilliance synchrotron radiation it has been possible to record a large number of weak superstructure spots due to charge ordering around the main peaks of the average structure. A study of the charge modulations with stage 3.5, and their behaviour as a function of the temperature and the intensity of the x-ray incident flux is reported. We are able to distinguish a microscopic decomposition in; 1) a stable domain, due to charges self trapped into a crystal of static ordered strings of finite length (~ 145 Å) and; 2) bubbles of 'superstripes' showing, as a function of photon dose, a decreasing coherence length at T=220 K.