Enhancement of phase separation in light Cu-doped La2CuO4+δ system: evidence from TEM and magnetization measurements

Cu-doped and undoped La2CuO4+delta samples prepared under the same conditions have been investigated. It is distinctly shown that phase separation only exists in Cu-doped one, in which a stripe structure was observed at room temperature. This leads to a suggestion as that Cu doping may promote phase separation and the stripe structure is directly related to the phase separation.