Anomalous Nernst effect in Ir₂₂Mn₇₈/Co₂₀Fe₆₀B₂₀/MgO layers with perpendicular magnetic anisotropy

The anomalous Nernst effect in perpendicularly magnetized Ir₂₂Mn₇₈/Co₂₀Fe₆₀B₂₀/MgO thin film is measured using well-defined in-plane temperature gradients.The geometry with out-of-plane magnetic field and in-plane temperature gradient is the natural configuration to avoid longitudinal spin Seebeck effect and allow a precise determination of the temperature gradient. The anomalous Nernst coefficient reaches 1.8 µV/K at room temperature, which is almost 50 times larger than that of Ta/Co₂₀Fe₆₀B₂₀/MgO thin film with perpendicular magnetic anisotropy. The anomalous Nernst and anomalous Hall results in different sample structures reveal that the large Nernst coefficient of Ir₂₂Mn₇₈/Co₂₀Fe₆₀B₂₀/MgO thin film is related to the interface between CoFeB and IrMn. Finally, we point out a possible application of ANE that takes advantage of the perpendicular magnetization to obtain large Nernst voltage, owing to the in-plane geometry of the device.