  Magnetic effects on chiral phase transition have been investigated in a
modified soft-wall AdS/QCD model, in which the dilaton field is taken to be
negative at the ultraviolet region and positive at the infrared region as in
Phys.Rev.D93(2016),101901 and JHEP1604(2016)036. The magnetic field is
introduced into the background geometry by solving the Einstein-Maxwell system.
After embedding the magnetized background geometry into the modified soft-wall
model, the magnetic field dependent behavior of chiral condensate is worked out
numerically. It is found that, in the chiral limit, the chiral phase transition
remains as a second order at finite magnetic field $B$, while the symmetry
restoration temperature and chiral condensate decrease with the increasing of
magnetic field in small $B$ region. When including finite quark mass effect,
the phase transition turns to be a crossover one, and the transition
temperature still decreases with increasing magnetic field $B$ when $B$ is not
very large. In this sense, inverse magnetic catalysis effect is observed in
this modified soft-wall AdS/QCD model.
