# Prediction of a Giant Magnetoelectric Cross-Caloric Effect Around a Tetracritical Point in Multiferroic SrMnO$_3$

## TL;DR

This paper predicts a giant magnetoelectric and electrocaloric effect in strain-engineered SrMnO3 near a tetracritical point, highlighting its potential for eco-friendly cooling technologies.

## Contribution

It provides realistic, first-principles-based predictions of enhanced magnetoelectric and electrocaloric effects in SrMnO3 near a tetracritical point, a novel insight for multiferroic materials.

## Key findings

- Electric field significantly alters antiferromagnetic order.
- Magnetoelectric response is several orders larger than in typical materials.
- Electrocaloric effect increases by about 60% due to magnetoelectric coupling.

## Abstract

We study the magnetoelectric and electrocaloric response of strain-engineered, multiferroic SrMnO$_3$, using a phenomenological Landau theory with all parameters obtained from \emph{first-principles}-based calculations. This allows to make realistic and materials-specific predictions about the magnitude of the corresponding effects. We find that in the vicinity of a tetracritical point, where magnetic and ferroelectric phase boundaries intersect, an electric field has a huge effect on the antiferromagnetic order, corresponding to a magnetoelectric response several orders of magnitude larger than in conventional linear magnetoelectrics. Furthermore, the strong magnetoelectric coupling leads to a magnetic, cross-caloric contribution to the electrocaloric effect, which increases the overall caloric response by about 60\%. This opens up new potential applications of antiferromagnetic multiferroics in the context of environmentally friendly solid state cooling technologies.