Achieving high-temperature ferromagnetism by means of magnetic ions dimerization

TL;DR

This paper proposes a method to achieve high-temperature ferromagnetism in two-dimensional materials by dimerizing magnetic ions, demonstrated with Mn$_2$N$_6$C$_6$ monolayer showing near-room-temperature Curie temperature.

Contribution

The study introduces magnetic ion dimerization as a strategy to enhance exchange coupling and stabilize ferromagnetism in 2D materials, with a specific example of Mn$_2$N$_6$C$_6$.

Findings

Mn$_2$N$_6$C$_6$ monolayer exhibits ferromagnetism with a Curie temperature of 272.3 K.

Dimerization of Mn ions enhances exchange interactions and stabilizes ferromagnetism.

The approach provides a pathway for designing high-temperature 2D ferromagnetic materials.

Abstract

Magnetic two-dimensional materials have potential application in next-generation electronic devices and have stimulated extensive interest in condensed matter physics and material fields. However, how to realize high-temperature ferromagnetism in two-dimensional materials remains a great challenge in physics. Herein, we propose an effective approach that the dimerization of magnetic ions in two-dimensional materials can enhance the exchange coupling and stabilize the ferromagnetism. Manganese carbonitride Mn$_2$N$_6$C$_6$ with a planar monolayer structure is taken as an example to clarify the method, in which two Mn atoms are gathered together to form a ferromagnetic dimer of Mn atoms and further these dimers are coupled together to form the overall ferromagnetism of the two-dimensional material. In Mn$_2$N$_6$C$_6$ monolayer, the near-room-temperature ferromagnetism with the Curie temperature of 272.3 K is determined by solving Heisenberg model using Monte Carlo simulations method.