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Title: Unidirectional spin-torque driven magnetization dynamics

Abstract

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.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1393468
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 95; Journal Issue: 22
Country of Publication:
United States
Language:
English

Citation Formats

Sklenar, Joseph, Zhang, Wei, Jungfleisch, Matthias B., Saglam, Hilal, Grudichak, Scott, Jiang, Wanjun, Pearson, John E., Ketterson, John B., and Hoffmann, Axel. Unidirectional spin-torque driven magnetization dynamics. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.224431.
Sklenar, Joseph, Zhang, Wei, Jungfleisch, Matthias B., Saglam, Hilal, Grudichak, Scott, Jiang, Wanjun, Pearson, John E., Ketterson, John B., & Hoffmann, Axel. Unidirectional spin-torque driven magnetization dynamics. United States. doi:10.1103/PhysRevB.95.224431.
Sklenar, Joseph, Zhang, Wei, Jungfleisch, Matthias B., Saglam, Hilal, Grudichak, Scott, Jiang, Wanjun, Pearson, John E., Ketterson, John B., and Hoffmann, Axel. Thu . "Unidirectional spin-torque driven magnetization dynamics". United States. doi:10.1103/PhysRevB.95.224431.
@article{osti_1393468,
title = {Unidirectional spin-torque driven magnetization dynamics},
author = {Sklenar, Joseph and Zhang, Wei and Jungfleisch, Matthias B. and Saglam, Hilal and Grudichak, Scott and Jiang, Wanjun and Pearson, John E. and Ketterson, John B. and Hoffmann, Axel},
abstractNote = {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.},
doi = {10.1103/PhysRevB.95.224431},
journal = {Physical Review B},
number = 22,
volume = 95,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}