Excitations of incoherent spin-waves due to spin-transfer torque

Kyung Jin Lee, Alina Deac, Olivier Redon, Jean Pierre Nozières, Bernard Dieny

Research output: Contribution to journalArticle

209 Citations (Scopus)

Abstract

The possibility of exciting microwave oscillations in a nanomagnet by a spin-polarized current, as predicted by Slonczewski1 and Berger 2, has recently been demonstrated3. This observation opens important prospects of applications in radiofrequency components. However, some unresolved inconsistencies are found when interpreting the magnetization dynamics within the coherent spin-torque model4-6. In some cases, the telegraph noise caused by spin-currents could not be quantitatively described by that model. This has led to controversy about the need for an effective magnetic temperature model7-11. Here we interpret the experimental results of Kiselev et al.3 using micromagnetic simulations. We point out the key role played by incoherent spin-wave excitation due to spin-transfer torque. The incoherence is caused by spatial inhomogeneities in local fields generating distributions of local precession frequencies. We observe telegraph noise with gigahertz frequencies at zero temperature. This is a consequence of the chaotic dynamics and is associated with transitions between attraction wells in phase space.

Original languageEnglish
Pages (from-to)877-881
Number of pages5
JournalNature Materials
Volume3
Issue number12
DOIs
Publication statusPublished - 2004 Dec
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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