  We recalculate the magnetic moment of neutrinos in a hot and dense medium.
The magnetic dipole moment of neutrinos is modified at high temperature and
chemical potential. We show that the magnetic dipole moment of electron
neutrino does not get a significant contribution from thermal background to
meet the cosmological bound. However, chemical potential contribution to the
magnetic moment is non-ignorable even when chemical potential is an order of
magnitude greater than the electron mass. It is demonstrated that this effect
is more significant in the models with an extended Higgs sector through
neutrino mixing.
