Quantitative characterization of the spin-orbit torque using harmonic Hall voltage measurements

Masamitsu Hayashi, Junyeon Kim, Michihiko Yamanouchi, Hideo Ohno

Research output: Contribution to journalArticlepeer-review

338 Citations (Scopus)


Solid understanding of current induced torques is a key to the development of current and voltage controlled magnetization dynamics in ultrathin magnetic heterostructures. To evaluate the size and direction of such torques, or effective fields, a number of methods have been employed. Here, we examine the adiabatic (low-frequency) harmonic Hall voltage measurement that has been used to study the effective field. We derive an analytical formula for the harmonic Hall voltages to evaluate the effective field for both out of plane and in-plane magnetized systems. The formula agrees with numerical calculations based on a macrospin model. Two different in-plane magnetized films, Pt|CoFeB|MgO and CuIr|CoFeB|MgO are studied using the formula developed. The effective field obtained for the latter system shows relatively good agreement with that estimated using spin torque switching phase diagram measurements reported previously. Our results illustrate the versatile applicability of harmonic Hall voltage measurement for studying current induced torques in magnetic heterostructures.

Original languageEnglish
Article number144425
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number14
Publication statusPublished - 2014 Apr 29

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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