Sign of inverse spin Hall voltages generated by ferromagnetic resonance and temperature gradients in yttrium iron garnet platinum bilayers

Abstract

The bon mot that the sign is the most difficult concept in physics since there are no approximate methods to determine it has been ascribed to Wolfgang Pauli. Indeed, the struggle to obtain correct signs permeates all of physics. While the negative sign of the electron charge is just a convention, that of derived properties, such as the (conventional) Hall voltage, has real physical meaning. Often it is much easier and sufficient to determine sign differences between related quantities. However, a complete understanding requires not only the relative but also the absolute sign. Here we address the sign of the (inverse) spin