# Optimizing configurations for determining the magnetic model based on ab-initio calculations

## TL;DR

This paper introduces a new strategy to optimize magnetic coupling determination using ab-initio calculations, Monte Carlo sampling, and model refinement, demonstrated on a specific material with an open-source software implementation.

## Contribution

It presents a novel method combining ab-initio calculations, Monte Carlo sampling, and model refinement for efficient magnetic coupling estimation.

## Key findings

- Effective magnetic configurations identified for Bi₃Mn₄O₁₂(NO₃)
- Coupling constants and error bounds estimated accurately
- Open source software automates the entire process

## Abstract

In this paper, it is presented a novel strategy to optimize the determination of magnetic couplings by using ab-initio calculations of the energy. This approach allows determining efficiently, in terms of a proposed effective magnetic spin model, an optimal set of magnetic configurations to be simulated by DFT methods. Moreover, a procedure to estimate the values of the coupling constants and their error bounds from the estimated energies is proposed. This method, based on Monte Carlo sampling, takes into account the accuracy of the ab - initio simulations. A strategy to refine models reusing previously computed configuration energies is also presented. We apply the method to determine a magnetic model for the recently synthesized material Bi$_3$Mn$_4$O$_{12}$(NO$_3$). Finally, an open source software that implements and automatizes the whole process is presented.