ALMA Band 3 polarimetric follow-up of a complete sample of faint PACO
  sources
  We present Atacama Large Millimeter/submillimiter Array (ALMA) high
sensitivity ($\sigma_P \simeq 0.4\,$mJy) polarimetric observations at
$97.5\,$GHz (Band 3) of a complete sample of $32$ extragalactic radio sources
drawn from the faint Planck-ATCA Co-eval Observations (PACO) sample
($b<-75^\circ$, compact sources brighter than $200\,$mJy at $20\,$GHz). We
achieved a detection rate of $~97\%$ at $3\,\sigma$ (only $1$ non-detection).
We complement these observations with new Australia Telescope Compact Array
(ATCA) data between $2.1$ and $35\,$GHz obtained within a few months and with
data published in earlier papers from our collaboration. Adding the co-eval
GaLactic and Extragalactic All-sky Murchison widefield array (GLEAM) survey
detections between $70\,$ and $230\,$MHz for our sources, we present spectra
over more than $3$ decades in frequency in total intensity and over about $1.7$
decades in polarization. The spectra of our sources are smooth over the whole
frequency range, with no sign of dust emission from the host galaxy at mm
wavelengths nor of a sharp high frequency decline due, for example, to electron
ageing. We do however find indications of multiple emitting components and
present a classification based on the number of detected components. We analyze
the polarization fraction behaviour and distributions up to $97\,$GHz for
different source classes. Source counts in polarization are presented at
$95\,$GHz.
