  Solid understanding of current induced torques is key to the development of
current and voltage controlled magnetization dynamics in ultrathin magnetic
heterostructures. A versatile technique is needed to evaluate such torques in
various systems. Here we examine the adiabatic (low frequency) harmonic Hall
voltage measurement that has been recently developed to study current induced
effective field that originate from the spin orbit effects. We analytically
derive a form that can be used to evaluate the harmonic Hall voltages and
extract relevant parameters in two representative systems, i.e. out of plane
and in-plane magnetized systems. Contributions from the anomalous Hall and
planar Hall effects are considered.
