  A linear stability analysis of ionized discs with a temperature gradient and
an external axial magnetic field is presented. It is shown that both
hydromagnetic and thermomagnetic effects can lead to the amplification of waves
and make discs unstable. The conditions under which the instabilities grow are
found and the characteristic growth rate is calculated. The regimes at which
both the thermomagnetic and magnetorotational instabilities can operate are
discussed.
