Working Paper Article Version 1 This version is not peer-reviewed

# Remarks on Nonsingular Models as Hayward and Magnetized Black Hole with Rational Nonlinear Electrodynamics

Version 1 : Received: 13 November 2020 / Approved: 16 November 2020 / Online: 16 November 2020 (16:04:52 CET)

How to cite: Il'ich Kruglov, S. Remarks on Nonsingular Models as Hayward and Magnetized Black Hole with Rational Nonlinear Electrodynamics. Preprints 2020, 2020110434 Il'ich Kruglov, S. Remarks on Nonsingular Models as Hayward and Magnetized Black Hole with Rational Nonlinear Electrodynamics. Preprints 2020, 2020110434

## Abstract

A Hayward black hole and magnetically charged black hole based on rational nonlinear electrodynamics with the Lagrangian ${\cal L} = -{\cal F}/(1+2\beta{\cal F})$ (${\cal F}$ is a field invariant) are considered. It was shown that the metric function in both models possesses a de Sitter core without singularities as $r\rightarrow 0$. The behavior of the Hawking temperature and the heat capacity in these models are similar. The phase transitions take place when the Hawking temperature has the maximum, and black holes are thermodynamically stable at some event horizon radii when the heat capacity is positive. We show that the source of gravity in the Hayward model is questionable.

## Keywords

Magnetically charged black holes; Hawking temperature;; heat capacity; phase transitions

## Subject

PHYSICAL SCIENCES, Acoustics

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