Two-Electron Model of the Anomalous Nernst Effect

Both the anomalous Hall and anomalous Nernst effects were first observed over a century ago, yet their microscopic mechanisms are not yet completely understood. In a previous study, we applied a Boltzmann model to demonstrate that a spin-dependent mean free path combined with interface scattering shapes the thickness dependence of the anomalous Hall effect in a thin-film ferromagnet. We also showed that modifying the boundary conditions of the FM layer by adding a NM cap can significantly change the anomalous Hall conductivity by influencing the current distribution in the FM in a spin-dependent way. Since the anomalous Hall and anomalous Nernst effect are linked by the Mott relation, we expect that any spin-dependent modification of the anomalous Hall conductivity will have a consequent effect on the thermoelectric conductivity. Here we investigate the thickness dependence of the anomalous Nernst effect in permalloy (Py = Ni₈₀Fe₂₀) and in Py/Cu/Py spin valve structures to gain a better understanding of the role of spin dependence in the microscopic mechanisms of the anomalous Nernst effect.