Linear frequency modulation by weak bipolar magnetic fields for a vortex-mode oscillation in a nanocontact magnetoresistive spin-torque-oscillator

Kosaku Miyake, Yoshihito Okutomi, Hiroshi Tsukahara, Hiroshi Imamura, Masashi Sahashi

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Spin torque oscillations near zero magnetic fields were investigated in a nanocontact magnetoresistive device. A typical auto-oscillation mode was observed with high amplitude and narrow linewidth in a vortex domain state of the free layer around the zero field. The number of branches was reduced to a single one with an increase of current over the threshold value. As a result, we observed a linear frequency change between a wider field range across zero fields with a high amplitude and a narrow linewidth for the oscillation. The frequency response to small bipolar applied fields is applicable to a weak-field sensor.

Original languageEnglish
Article number113001
JournalApplied Physics Express
Volume6
Issue number11
DOIs
Publication statusPublished - 2013 Nov 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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