Magneto Seebeck effect in REFeAsO (RE=rare earth) compounds: probing the magnon drag scenario

TL;DR

This study explores the Seebeck effect in REFeAsO compounds, revealing a magnetic field-enhanced feature linked to magnon drag, providing insights into electron-magnon interactions relevant for superconductivity.

Contribution

The paper develops a model for magnon drag contribution to the Seebeck effect in REFeAsO compounds, connecting magnetic fluctuations to thermoelectric behavior.

Findings

Magnetic field enhances the Seebeck bump around 50K.

Model successfully explains temperature and field dependence of the Seebeck effect.

Provides insights into electron-antiferromagnetic spin fluctuation coupling.

Abstract

We investigate Seebeck effect in REFeAsO (RE=rare earth)compounds as a function of temperature and magnetic field up to 30T. The Seebeck curves are characterized by a broad negative bump around 50K, which is sample dependent and strongly enhanced by the application of a magnetic field. A model for the temperature and field dependence of the magnon drag contribution to the Seebeck effect by antiferromagnetic (AFM) spin fluctuation is developed. It accounts for the magnitude and scaling properties of such bump feature in our experimental data. This analysis allows to extract precious information on the coupling between electrons and AFM spin fluctuations in these parent compound systems, with implications on the pairing mechanism of the related superconducting compounds.