  Source-free equations of nonlinear electrodynamics minimally coupled to
gravity (NED-GR) admit regular axially symmetric asymptotically Kerr-Newman
solutions, which describe electrically charged rotating black holes and
spinning solitons. Asymptotic analysis of solutions shows the existence of de
Sitter vacuum interior which has the properties of a perfect conductor and an
ideal diamagnetic. The Kerr ring singularity (a naked singularity in the case
without horizons) is replaced with a superconducting current, which serves as a
nondissipative source of the Kerr-Newman fields and can be responsible for an
unlimited life time of a spinning object.
