  A coupled spin-electron diamond chain with localized Ising spins placed on
its nodal sites and mobile electrons delocalized over interstitial sites is
explored in a magnetic field taking into account the difference between Land\'e
g-factors of the localized spins and mobile electrons. The ground-state phase
diagram is constituted by two classical ferrimagnetic phases, the quantum
unsaturated paramagnetic phase and the saturated paramagnetic phase. Both
classical ferrimagnetic phases as well as the unsaturated paramagnetic phase
are reflected in a low-temperature magnetization curve as intermediate
magnetization plateaus. The unsaturated paramagnetic phase is quantum in its
character as evidenced by the fermionic concurrence calculated for a pair of
the mobile electrons hopping in between the interstitial sites. It is shown
that the magnetic field can under certain conditions induce a quantum
entanglement above the disentangled ground state.
