Magnetodielectric coupling in a Ru-based 6H-perovskite, Ba3NdRu2O9

TL;DR

This study demonstrates magnetodielectric coupling in the Ru-based 6H-perovskite Ba3NdRu2O9, revealing temperature-dependent mechanisms and magnetic field effects that advance understanding of such interactions in higher d-orbital materials.

Contribution

First demonstration of magnetodielectric coupling in a Ru-based 6H-perovskite with insights into temperature and magnetic field control mechanisms.

Findings

Magnetodielectric coupling observed below 24 K.

Dielectric constant peaks at magnetic transition, suppressed by magnetic field.

Sign change in magnetodielectric coupling around 17 K.

Abstract

A large spin-orbit coupling is a way to control strong magnetodielectric (MD) coupling in a higher d-orbital materials. However reports are rare on such compounds due to often leaky conductive behavior. Here, we demonstrate MD coupling in a Ru-based 6H-perovskite system, Ba3NdRu2O9. The rare-earth ion in a 6H-perovskite makes the system insulating enough to carry out MD investigation. The compound is ferromagnetically ordered below 24 K (TC), followed by another magnetic feature at T~ 17 K (T2). The dielectric constant clearly traces the magnetic ordering, manifesting a peak at the onset of TC, which is suppressed by the application of an external magnetic field (H). The results indicate the presence of MD coupling in this compound, which is further confirmed by the H-dependence of the dielectric constant. Interestingly, a cross-over of the sign of MD coupling is observed at T ~ T2. We conclude that two different mechanism controls the MD coupling which yields positive and negative coupling, respectively. Both mechanisms are competing as a function of temperature and magnetic field. This brings us a step closer to design and control the magnetodielectric effect in 6H-perovskites containing higher d-orbital elements.