Asymptotic Reissner-Nordstrom solution within nonlinear electrodynamics

A model of nonlinear electrodynamics coupled with the gravitational field is studied. We obtain the asymptotic black hole solutions at r -> 0 and r -> 8. The asymptotic at r -> 0 is shown, and we find corrections to the Reissner-Nordstrom solution and Coulomb's law at r -> 8. The mass of the black hole is evaluated having the electromagnetic origin. We investigate the thermodynamics of charged black holes and their thermal stability. The critical point corresponding to the second-order phase transition (where heat capacity diverges) is found. If the mass of the black hole is greater than the critical mass, the black hole becomes unstable.