# Half-metallic ferromagnetism in Sr$_3$Ru$_2$O$_7$

## TL;DR

This study uses first-principles calculations to reveal that Sr$_3$Ru$_2$O$_7$ has a ferromagnetic half-metallic ground state, with potential for phase transitions influenced by structural distortions.

## Contribution

It provides detailed electronic, magnetic, and structural insights into Sr$_3$Ru$_2$O$_7$, highlighting the competition between ferromagnetic and antiferromagnetic phases.

## Key findings

- Sr$_3$Ru$_2$O$_7$ is a ferromagnetic half-metal.
- The ferromagnetic state competes with an antiferromagnetic metallic phase.
- Magnetic properties are unaffected by RuO$_6$ octahedra rotations.

## Abstract

The bilayered member of the Ruddesden-Popper family of ruthenates, Sr$_3$Ru$_2$O$_7$, has received an increasing attention due to its interesting properties and phases. By using first principle calculations we find that the ground-state is characterized by a ferromagnetic (FM) half-metallic state. This state strongly competes with an antiferromagnetic metallic phase, which indicates the possible presence of a particular state characterized by the existence of different magnetic domains. To drive the system towards a phase transition we studied the electronic and magnetic properties as a function of RuO$_6$ octahedra rotations and found that the magnetic phase does not couple with the rotation angle. Our results provide accurate electronic, structure, and magnetic ground-state properties of Sr$_3$Ru$_2$O$_7$ and stimulate the investigation of other type of octahedra rotations and distortions in the search of phase transitions.