Altermagnetic-Like Behavior and Enhanced Coercivity in Ferrimagnets at a Critical Point of an Extended N\'eel-Diagram

TL;DR

This paper extends the Ne9el diagram for ferrimagnets, identifying a critical point where magnetic compensation persists below Curie temperature, leading to altermagnetic-like behavior and increased coercivity, with practical design insights.

Contribution

It introduces an extended Ne9el diagram capturing a critical point in ferrimagnets, guiding the engineering of materials with enhanced magnetic properties.

Findings

Identification of a critical point with full magnetic compensation below Curie temperature.

Ferrimagnets at this point exhibit altermagnetic-like features and higher coercivity.

Design principles for tuning ferrimagnets via chemical substitution demonstrated through simulations.

Abstract

We generalize the classic N\'eel diagram for ferrimagnets within a mean-field framework and reveal a critical point at which full magnetic compensation is maintained below the Curie temperature and extends past the nominal compensation point. Ferrimagnets tuned to this critical point display altermagnetic-like features and markedly enhanced coercive fields. We show that proximity to this regime requires minimizing the net local moment while balancing exchange interactions with respect to the number of equivalent atoms in each sublattice. The resulting extended N\'eel diagram provides practical design principles for engineering ferrimagnets near the critical point via targeted chemical substitution that combines atoms with robust and weak local moments, as demonstrated through density functional theory and Monte Carlo simulations for GdCo$_5$-type ferrimagnets.