IS THE TETRAGONAL OVERDOPED PHASE (LA,SR)2CUO4 SUPERCONDUCTIVE

Comparative studies of Meissner and shielding processes have been performed on variously sized samples of the solid solution (La1-xSrx)2CuO4: (polycrystalline, powder, and single-crystalline) under various magnetic fields in the range 0.03-10 Oe. Considering the kinetics of the two processes, this systematic approach has indicated that the observed Meissner signal can be significantly low with the sample still being wholly superconductive. Based on this comparative study, the tetragonal region of (La1-xSrx)2 CuO4 with x greater than 0.105 has been concluded to be superconductive, suggesting the nonessential involvement of the buckling of the Cu-O-Cu-O bond in the CuO2 layer in the manifestation of superconductivity.