Unidirectional spin-torque driven magnetization dynamics

Article

关键词: MAGNETORESISTANCE;    MULTILAYERS;    EXCITATION;    MAGNITUDE;    RESONANCE;    WAVES;    FILMS;   

DOI  :  10.1103/PhysRevB.95.224431

来源: SCIE

【 摘 要 】

The rich physics associated with magnetism often centers around directional effects. Here we demonstrate how spin-transfer torques in general result in unidirectional ferromagnetic resonance dynamics upon field reversal. The unidirectionality is a direct consequence of both field-like and damping-like dynamic torques simultaneously driving the motion. This directional effect arises from the field-like torque being odd and the damping-like torque being even under field reversal. The directional effect is observed when the magnetization has both an in-plane and out-of-plane component, since then the linear combination of the torques rotates with a different handedness around the magnetization as the magnetization is tipped out-of-plane. The effect is experimentally investigated via spin-torque ferromagnetic resonance measurements with the field applied at arbitrary directions away from the interface normal. The measured asymmetry of the voltage spectra are well explained within a phenomenological torque model.

【 授权许可】

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