  Polarized component maps in the Northern Sky are derived from the QUIJOTE-MFI
wide survey data at 11 and 13 GHz, the WMAP K and Ka bands and all Planck
polarized channels using the parametric component separation method B-SeCRET.
The addition of QUIJOTE-MFI data significantly improves the uncertainty in the
parameter estimation of the low frequency dominant foreground, in particular
the estimation of the synchrotron spectral index. We find statistically
significant spatial variability across the sky. A power law model of the
synchrotron emission provides a good fit of the data outside the galactic plane
but fails to track the complexity of this region. Moreover, when we assume a
synchrotron model with uniform curvature we find, in the 95% confidence region,
a non-zero $c_s$ value. However, there is not sufficient statistical
significance to determine which model is favoured.
