Measurement of nonlinear frequency shift coefficient in spin-torque oscillators based on MgO tunnel junctions

Kiwamu Kudo; Tazumi Nagasawa; Rie Sato; Koichi Mizushima

doi:10.1063/1.3176939

Measurement of nonlinear frequency shift coefficient in spin-torque oscillators based on MgO tunnel junctions

Materials Science 2015-05-13 v1 Other Condensed Matter

Authors: Kiwamu Kudo , Tazumi Nagasawa , Rie Sato , Koichi Mizushima

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Abstract

The nonlinear frequency shift coefficient, which represents the strength of the transformation of amplitude fluctuations into phase fluctuations of an oscillator, is measured for MgO-based spin-torque oscillators by analyzing the current dependence of the power spectrum. We have observed that linewidth against inverse normalized power plots show linear behavior below and above the oscillation threshold as predicted by the analytical theories for spin-torque oscillators. The magnitude of the coefficient is determined from the ratio of the linear slopes. Small magnitude of the coefficient has been obtained for the device exhibiting narrow linewidth at high bias current.

Keywords

nanomechanical resonators

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@article{arxiv.0906.5224,
  title  = {Measurement of nonlinear frequency shift coefficient in spin-torque oscillators based on MgO tunnel junctions},
  author = {Kiwamu Kudo and Tazumi Nagasawa and Rie Sato and Koichi Mizushima},
  journal= {arXiv preprint arXiv:0906.5224},
  year   = {2015}
}

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4 pages, 5 figures; accepted for publication in Applied Physics Letters

Measurement of nonlinear frequency shift coefficient in spin-torque oscillators based on MgO tunnel junctions

Abstract

Keywords

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