From Ferromagnet to Antiferromagnet: Dimensional Crossover in (111) SrRuO3 Ultrathin Films

TL;DR

This study reveals that reducing the thickness of (111) SrRuO3 films transforms their ground state from metallic ferromagnetism to semiconducting antiferromagnetism, enabling new functionalities for spintronics.

Contribution

It demonstrates a dimensional crossover in SrRuO3 films, showing a transition from ferromagnetic to antiferromagnetic states in the ultrathin limit on a (111) crystal plane.

Findings

Transition from metallic ferromagnet to semiconducting antiferromagnet at ultrathin thicknesses

Emergence of twelve-fold anisotropic magnetoresistance in ultrathin films

First-principles calculations confirm A-type antiferromagnetic order as stable ground state

Abstract

SrRuO3 is a canonical itinerant ferromagnet, yet its properties in the extreme two-dimensional limit on a (111) crystal plane remain largely unexplored. Here, we demonstrate a complete transformation of its ground state driven by dimensional reduction. As the thickness of (111)-oriented SrRuO3 films is reduced to a few unit cells, the system transitions from a metallic ferromagnet to a semiconducting antiferromagnet. This emergent antiferromagnetism is evidenced by a vanishing magnetic remanence and most strikingly, by the appearance of an unconventional twelve-fold anisotropic magnetoresistance. First-principles calculations confirm that an A-type antiferromagnetic order is the stable ground state in the ultrathin limit. Our findings establish (111) dimensional engineering as a powerful route to manipulate correlated electron states and uncover novel functionalities for antiferromagnetic spintronics.