Dependence of transverse magneto-thermoelectric effects on inhomogeneous magnetic fields

TL;DR

This study investigates how inhomogeneous magnetic fields influence transverse magneto-thermoelectric effects in permalloy films, revealing artifacts that challenge the detection of the transverse spin Seebeck effect.

Contribution

It demonstrates that small parasitic magnetic fields can cause artifacts in measurements, providing new insights into uncertainties in detecting the transverse spin Seebeck effect.

Findings

Parasitic magnetic fields below 1 Oe produce artifacts around 1% of the thermopower amplitude.

Artifacts can obscure the true transverse spin Seebeck effect signals.

The contribution of the transverse spin Seebeck effect is below 20 nV noise level.

Abstract

Transverse magneto-thermoelectric effects are studied in permalloy thin films grown on MgO substrates. We find that small parasitic magnetic fields below 1 Oe can produce artifacts of the order of 1 % of the amplitude of the anisotropic magneto-thermopower which is also detected in the experiments. The measured artifacts reveal a new source of uncertainties for the detection of the transverse spin Seebeck effect. Taking these results into account we conclude that the contribution of the transverse spin Seebeck effect to the detected voltages is below the noise level of 20 nV.