  We report the observation of a magnetic field assisted transient
superconducting state in the two dimensional electron gas existing at the
interface of LaAlO$_3$/SrTiO$_3$ heterostructures. This metastable state
depends critically on the density of charge carriers in the system. It appears
concomitantly with a Lifshitz transition as a consequence of the interplay
between ferromagnetism and superconductivity and the finite relaxation time of
the in-plane magnetization. Our results clearly demonstrate the inherently
metastable nature of the superconducting state competing with a magnetic order
in these systems. The co-existence of superconductivity and ferromagnetism in
the conducting electronic layer formed at the interface of insulating oxides
has thrown up several intriguing and as yet unanswered questions. An open
question in this field is the energetics of the interplay between these two
competing orders and the present observation goes a long way in understanding
the underlying mechanism.
