Field tunable spin density wave phases in Sr3Ru2O7

TL;DR

This study demonstrates that applying a magnetic field to Sr3Ru2O7 induces and tunes spin-density-wave magnetic orders, revealing a new mechanism linked to electronic structure and magnetic fluctuations that also explains its resistivity anisotropy.

Contribution

The paper shows that magnetic fields can induce and control SDW phases in Sr3Ru2O7, a phenomenon not observed without the field, highlighting a novel mechanism involving electronic structure near the Fermi energy.

Findings

Magnetic field induces SDW order in Sr3Ru2O7.

SDW states are tunable over small field ranges (<0.4T).

Magnetic field direction influences SDW domain populations.

Abstract

The conduction electrons in a metal experience competing interactions with each other and the atomic nuclei. This competition can lead to many types of magnetic order in metals. For example, in chromium the electrons order to form a spin-density-wave (SDW) antiferromagnetic state. A magnetic field may be used to perturb or tune materials with delicately balanced electronic interactions. Here we show that the application of a magnetic field can induce SDW magnetic order in a metal, where none exists in the absence of the field. We use magnetic neutron scattering to show that the application of a large (~8T) magnetic field to the metamagnetic perovskite metal Sr3Ru2O7 can be used to tune the material through two magnetically-ordered SDW states. The ordered states exist over relatively small ranges in field (<0.4T) suggesting that their origin is due to a new mechanism related to the electronic fine structure near the Fermi energy, possibly combined with the stabilising effect of magnetic fluctuations. The magnetic field direction is shown to control the SDW domain populations which naturally explains the strong resistivity anisotropy or electronic nematic behaviour observed in this material.