  Direct collapse black holes (DCBHs) are the leading candidates for the origin
of the first supermassive black holes. However, the role of magnetic fields
during their formation is still unclear as none of the previous studies has
been evolved long enough to assess their impact during the accretion phase.
Here, we report the results from a suite of 3D cosmological
magneto-hydrodynamic (MHD) simulations which are evolved for 1.6 Myrs
comparable to the expected lifetime of supermassive stars (SMSs). Our findings
suggest that magnetic fields are rapidly amplified by strong accretion shocks
irrespective of the initial magnetic field strength and reach the saturation
state. They stabilize the accretion disks and significantly reduce
fragmentation by enhancing the Jeans mass in comparison with pure
hydrodynamical runs. Although the initial clump masses are larger in MHD runs,
the rapid coalescence of clumps in non-MHD cases due to the higher degree of
fragmentation results in similar masses. Overall, the central clumps have
masses of $\rm 10^5~M_{\odot}$ and the mean mass accretion rates of $\rm \sim
0.1 ~M_{\odot}/yr$ are similar in both MHD and non-MHD cases. The multiplicity
of SMSs is significantly reduced in MHD simulations. Such strongly amplified
magnetic fields are expected to launch Jets and outflows which may be detected
with upcoming radio telescopes.
