Anomalous Nernst effect in La0.5Ca0.5Coo3

TL;DR

This study demonstrates the presence of the anomalous Nernst effect in La0.5Ca0.5CoO3, revealing its dependence on ferromagnetic transport properties and showing potential for magnetic field-free thermoelectric applications.

Contribution

It reports the observation of the anomalous Nernst effect in a polycrystalline perovskite, highlighting its relation to ferromagnetic phases and transport properties, which was not previously documented for this material.

Findings

ANE occurs in La0.5Ca0.5CoO3 below TC=147 K.

ANE depends on ferromagnetic phase transport properties.

Polycrystalline sample shows ANE without external magnetic field.

Abstract

We report the occurrence of the anomalous Nernst effect (ANE) in polycrystalline perovskite La0.5Ca0.5CoO3. The sample is ferromagnetic below TC = 147 K and resistivity shows non-metallic behavior above and below the TC with only a small negative magnetoresistance (~2%) around TC. Field dependence of magnetization at 10 K shows large hysteresis with a coercive field of 6 kOe but a small magnetization ~ 0.64 Bohr magneton/Co even in a field of 50 kOe, which indicates the presence of magnetically heterogeneous ground state consisting of ferromagnetic and non-ferromagnetic phases. The field dependence of the Nernst thermopower (Sxy) at low temperatures shows complete saturation but the magnetization does not. This indicates that the ANE in La0.5Ca0.5CoO3 depends only on the transport properties of the ferromagnetic phase, while it is not affected by the non-ferromagnetic phase. Due to the higher value of remnant Sxy, the magnetized polycrystalline sample exhibits ANE in absence of an external magnetic field.