Peculiar behaviour of the spin susceptibility in Bi2Sr2Ca2Cu3O10

The temperature dependence of the Cu-63 Nh LR shifts and spin lattice relaxation rates was measured for a (Bi0.93Pb0.07)(2.1)Sr2Ca2Cu3O10 sample, in a powder and a magnetically aligned form. In the last case, two resonance lines were observed from Cu in the inner and the outer Cu-O planes. The inner plane Cu, which is in a symmetric local environment, has a small quadrupolar frequency nu(Q) = 5.4 MHz (nu(Q) = e(2)qQ/2h), while the outer plane one has nu(Q) > 15 MHz. Comparison of the Cu-63 (perpendicular to) with the O-17(iso) shifts from the same Cu-O planes shows that they are proportional to the same spin susceptibility. The temperature dependence of (T1,(u)T)(-1) fur the unaligned sample (inner plane resonance) shows a peak at 160 K, while (T1c,(o)T)(-1) for the outer Cu-O planes peaks at 95 K. Strong antiferromagnetic fluctuations of the electron spins exist in the inner Cu-O planes. (C) 1999 Elsevier Science B.V. All rights reserved.