Relationship between charge stripe order and structural phase transitions in La1.875Ba0.125-xSrxCuO4 -: art. no. 134512

The nature of charge stripe order and its relationship with structural phase transitions were studied using synchrotron x-ray diffraction in La1.875Ba0.125-xSrxCuO4 (0.05less than or equal toxless than or equal to0.10). For x=0.05, as temperature increased, incommensurate superlattice peaks associated with the charge order disappeared just at the structural phase transition temperature, T-d2. However, for x=0.075 and 0.09, the superlattice peaks still existed as a short range correlation even above T-d2, indicating a precursor of charge ordering. Furthermore, temperature dependences of the superlattice peak intensity, correlation length, and incommensurability for x=0.05 are different from those for x=0.075 and 0.09. These results suggest that the transition process into the charge stripe order strongly correlates with the order of the structural phase transitions. A quantitative comparison of the structure factor associated with the charge order have been also made for all the samples.