# Optimal uni-axial ferromagnetism in (La,Ce)$_2$Fe$_{14}$B for permanent magnets

## TL;DR

This study uses first-principles calculations to explore the magnetic properties of La-Ce-Fe-B compounds, aiming to optimize their potential as permanent magnets with a focus on structure stability, magnetization, and anisotropy.

## Contribution

It provides a detailed first-principles analysis of La-Ce-Fe-B compounds, identifying optimal compositions balancing magnetic performance and stability.

## Key findings

- Ce-rich compounds have good stability and magnetic properties.
- Ce$_2$Fe$_{14}$B has a low Curie temperature of 120 K.
- Optimal compositions are identified based on ab initio data and practical considerations.

## Abstract

Prospects for light-rare-earth-based permanent magnet compound R$_{2}$Fe$_{14}$B (R=La$_{1-x}$Ce$_{x}$ with $0 \le x\le 1$) are inspected from first principles referring to the latest experimental data. Ce-rich 2:14:1 compounds come with good structure stability, reasonably good combination of magnetization and magnetic anisotropy, while a drawback lies in the low Curie temperature that is only 120~K above the room temperature at the Ce$_2$Fe$_{14}$B limit. Best compromise is inspected on the basis of ab initio data for (La$_{1-x}$Ce$_{x}$)$_2$Fe$_{14}$B referring to the magnetic properties of the champion magnet compound Nd$_{2}$Fe$_{14}$B and prerequisite conditions imposed by practical utility.