  Oscillations of the giant magnetoresistance (GMR) and thermo-electric power
(TEP) vs. both the thickness of the non-magnetic spacer and also that of the
ferromagnetic slabs are studied in the current-perpendicular-to-plane (CPP)
geometry of magnetic trilayer systems, in terms of a single-band tight-binding
model without impurities. The spin-dependent conductance has been calculated
from the Kubo formula by means of a recursion Green's function method and the
semi-infinite ideal-lead wires trick. Additionally the TEP is obtained directly
from Mott's formula. In general, the thickness oscillations of the GMR and the
TEP may have just one or two (short and long) oscillations. The long period,
related to spectacular beats, is apparently of non-RKKY type. The TEP
oscillations are strongly enhanced with respect to those of the GMR, have the
same periods, but different phases and a negative bias.
