NMR study on the local structure in La-based high-Tc cuprates
  To date, there has been no evidence for the macroscopic structural phase transition to the low temperature tetragonal structure (LTT) with a space group P42/ncm in high-TC cuprate of rare earth-free La2-xSrxCuO4 (LSCO). By investigating Cu-NMR on single crystals, we have found that spatially incoherent LTT structure emerges below 50 K in the sample with x=0.12. This incoherent structure is considered to play a key role for the slight depression of the superconductivity around x=1/8. 
T. Goto, J. Tonishi, T. Suzuki, A. Oosawa, M. Fujita, K. Yamada, T.   Adachi, Y. Koike