  Slow-mode shocks are important in understanding fast magnetic reconnection,
jet formation and heating in the solar atmosphere, and other astrophysical
systems. The atmospheric conditions in the solar chromosphere allow both
ionised and neutral particles to exist and interact. Under such conditions,
fine substructures exist within slow-mode shocks due to the decoupling and
recoupling of the plasma and neutral species. We study numerically the fine
substructure within slow-mode shocks in a partially ionised plasma, in
particular, analysing the formation of an intermediate transition within the
slow-mode shock. High-resolution 1D numerical simulations are performed using
the (P\underline{I}P) code using a two-fluid approach. We discover that
long-lived intermediate (Alfven) shocks can form within the slow-mode shock,
where there is a shock transition from above to below the Alfven speed and a
reversal of the magnetic field across the shock front. The collisional coupling
provides frictional heating to the neutral fluid, resulting in a
Sedov-Taylor-like expansion with overshoots in the neutral velocity and neutral
density. The increase in density results in a decrease of the Alfven speed and
with this the plasma inflow is accelerated to above the Alfven speed within the
finite width of the shock leading to the intermediate transition. This process
occurs for a wide range of physical parameters and an intermediate shock is
present for all investigated values of plasma-$\beta$, neutral fraction, and
magnetic angle. As time advances the magnitude of the magnetic field reversal
decreases since the neutral pressure cannot balance the Lorentz force. The
intermediate shock is long-lived enough to be considered a physical structure,
independent of the initial conditions.
