# Strain Tuning of Weyl Nodes in SrRuO3 Membranes

## TL;DR

This paper explores how strain affects the electronic and magnetic properties of SrRuO3 membranes, revealing the role of Weyl Fermions and electromechanical coupling.

## Contribution

The study introduces strain-free SrRuO3 membranes and demonstrates strain tuning of Weyl nodes and magnetoelectric properties.

## Key findings

- Strain-free SrRuO3 membranes show ferromagnetism with a Curie temperature of 150 K.
- Negative longitudinal magnetoresistance indicates the involvement of Weyl Fermions in transport.
- A sign change in magnetotransport suggests strain-induced changes in Fermi velocity of Weyl Fermions.

## Abstract

Free-standing membranes are an exciting recent development
in the
field of complex oxides, allowing intrinsic material properties and
phenomena to be probed in ways that would be difficult or otherwise
inaccessible in epitaxially bound heterostructures. By employment
of a water-soluble sacrificial layer of Sr3Al2O6, strain-free ultrathin SrRuO3 membranes
have been fabricated that exhibit bulk lattice parameters and ferromagnetism
at a Curie temperature of 150 K with the magnetic easy axis oriented
22° off the normal. The presence of sizable negative longitudinal
magnetoresistance provides a direct signature of the decisive role
played by Weyl Fermions in magnetotransport. In addition, a sign change
between the strained films and free-standing SrRuO3 membranes
of in-plane transversal magnetotransport indicates a strong electromechanical
coupling, resulting in a change of the Fermi velocity of Weyl Fermions.
Our measurements provide a first insight into the magnetoelectric
properties of SrRuO3 membranes, highlighting the influence
of the exfoliation process on structural, electronic, and magnetic
degrees of freedom.