  We present a detailed dielectric study of the relaxation effects that occur
in several perovskite rare-earth manganites, including the multiferroics TbMnO3
and DyMnO3. We demonstrate that the strong magnetocapacitive effects, observed
for electrical fields E||c, are nearly completely governed by magnetic-state
induced changes of the relaxation parameters. The multiferroic materials, which
undergo a transition into a spiral magnetic state, show qualitatively different
relaxation behavior than those compounds transferring into an A-type
antiferromagnetic state. We ascribe the relaxations in both cases to the
off-center motion of the manganese ions, which in the multiferroic systems also
leads to the ferroelectric ordering.
