  We present measurements of tunneling magneto-resistance (TMR) in single-wall
carbon nanotubes attached to ferromagnetic contacts in the Coulomb blockade
regime. Strong variations of the TMR with gate voltage over a range of four
conductance resonances, including a peculiar double-dip signature, are
observed. The data is compared to calculations in the "dressed second order"
(DSO) framework. In this non-perturbative theory, conductance peak positions
and linewidths are affected by charge fluctuations incorporating the properties
of the carbon nanotube quantum dot and the ferromagnetic leads. The theory is
able to qualitatively reproduce the experimental data.
