  We use the gauge/gravity correspondence to study the thermodynamics of a
magnetized quark-gluon plasma in the presence of a scalar operator of dimension
$\Delta=2$. We proceed by working in a five-dimensional gauged supergravity
theory, where we numerically construct an asymptotically AdS$_5$ background
that describes a black D3-brane in the presence of a magnetic and a scalar
fields. We study the asymptotic behavior of the background and its fields close
to the AdS$_5$ region to latter perform a thermodynamic analysis of the
solution that includes the renormalization of the free energy associated to it.
We find that because of the presence of the scalar operator, there exists a
maximum intensity for the magnetic field that the plasma can hold, while for
any given intensity smaller than that value, there are two states that differ
in their vacuum expectation value for the scalar operator. We show that one of
the two branches just mentioned is thermodynamically favored over the other.
