Intrinsic anomalous transverse electrical and thermoelectric effects in amorphous CoFeB thin films

Amorphous CoFeB, a soft ferromagnetic material with low magnetic damping, high saturation magnetization, and high spin polarization, has gained significant attention for spintronic applications. However, the increasing demand for higher-speed and higher-capacity data storage devices has led to growing energy consumption concerns. The anomalous Nernst effect (ANE), a transverse thermoelectric phenomenon, offers a promising solution to address this energy challenge in spintronic devices, however, the origin of ANE in amorphous CoFeB is not well understood yet. While previous studies have independently explored the anomalous Hall effect (AHE) and ANE in amorphous CoFeB, a comprehensive investigation combining both effects which can provide deeper insights into the underlying mechanisms is missing. By studying the temperature dependence of AHE and ANE, we have been able to evaluate critical parameters such as longitudinal and transverse electrical and thermoelectric conductivities, as well as Hall and Nernst angles. Our findings suggest a significant contribution from intrinsic mechanism, i.e., from local Berry curvature, to the anomalous transverse electrical and thermoelectric effects in amorphous CoFeB thin films. The observed intrinsic contribution is particularly notable given the challenges associated with studying the electronic structure of amorphous materials.