High level oscillations with narrow linewidth in magnetic nano-contact spin torque oscillator with synthetic AF spin-valve structure

Hiroaki Endo, Toshiyuki Tanaka, Masaaki Doi, Susumu Hashimoto, Hiromi Niu Fuke, Hitoshi Iwasaki, Masashi Sahashi

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

We investigated the current induced magnetization dynamics, so called spin torque oscillation, in magnetic nano-contact MR element with a synthetic antiferromagnetic type spin-valve structure under high in-plane applied magnetic field of 0.9-1 kOe. Very high level oscillation of 18 nVHz-1/2 with narrow FWHM of 12 MHz was observed in the condition of negative applied current where electron-spin is injected from free layer to reference one. Applied current dependency on an oscillation frequency is a blueshift with good linearlity, and same dependency on level and FWHM is almost constant in the range of-10 to-14 mA, while applied field dependency on frequency shows redshift with two different slopes, -2.5 MHz/Oe in less than 1 kOe and-8.7 MHz/Oe in more than 1 kOe which field is smaller than the spin-flop field for the synthetic antiferromagnet, besides very clear and reasonable peak and bottom for oscillation level and FWHM are observed, respectively. It is thought that these magnetization dynamics are originated from synthetic antiferromagnet.

Original languageEnglish
Article number5257221
Pages (from-to)3418-3421
Number of pages4
JournalIEEE Transactions on Magnetics
Volume45
Issue number10
DOIs
Publication statusPublished - 2009 Oct

Keywords

  • Index Terms-Magnetic nano-contact magnetoresistance
  • Magnetization dynamics
  • Microwave oscillation
  • Spin transfer torque
  • Synthetic antiferromagnet

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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