  The corona, a hot cloud of electrons close to the centre of the accretion
disc, produces the hard X-ray power-law continuum commonly seen in luminous
Active Galactic Nuclei (AGN). The continuum has a high-energy turnover,
typically in the range of one to several 100 keV and is suggestive of
Comptonization by thermal electrons. We are studying hard X-ray spectra of AGN
obtained with NuSTAR after correction for X-ray reflection and under the
assumption that coronae are compact, being only a few gravitational radii in
size as indicated by reflection and reverberation modelling. Compact coronae
raise the possibility that the temperature is limited and indeed controlled by
electron-positron pair production, as explored earlier (Paper I). Here we
examine hybrid plasmas in which a mixture of thermal and nonthermal particles
is present. Pair production from the nonthermal component reduces the
temperature leading to a wider temperature range more consistent with
observations.
