CU-63/65 LA-139-NMR STUDY ON ANTIFERROMAGNETIC ORDERING IN HIGH-T-C OXIDES LA2-XSRXCUO4 (X-CONGRUENT-TO-0.115) AND LA2-XBAXCUO4 (X-CONGRUENT-TO-0.125)

La-based high-T-c oxides La2-xBaxCuO4 (LBCO) and La2-xSrxCuO4 (LSCO) show a local minimum in the curve of T-c versus x around 0.125 for LBCO and around 0.115 for LSCO. in order to investigate the origin of this local minimum, temperature dependence of (CU)-C-63/65/La-139-NMR/NQR spectra has been studied on spray-dry-made samples with various Ba/Sr-concentrations. Existence of the antiferromagnetic ordering was confirmed by a significant broadening in the resonance lines at low temperatures below 35 K for LBCO (x congruent to 0.125) and 32 K for LSCO (x congruent to 0.115). By the analysis on the anisotropy in the broadening, the direction of the ordered field was found to be within the CuO plane. The hyperfine field and the Neel temperature showed a maximum at the Ba/Sr-concentration around which T-c is most suppressed, suggesting the crucial interplay between the antiferromagnetic ordering, and the suppression in T-c.