Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer

Yuki Kawada; Hiroshi Naganuma; Ahmet Serdar Demiray; Mikihiko Oogane; Yasuo Ando

doi:10.1063/1.4892077

Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer

Yuki Kawada, Hiroshi Naganuma, Ahmet Serdar Demiray, Mikihiko Oogane, Yasuo Ando

Tohoku University

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

Current-induced microwave spectra were measured in small-sized giant magnetoresistance devices composed of a NiFe vortex free layer and an out-of-plane magnetized Co/Pd multilayer polarizer. The influence of a large direct current (DC) and a bias field on the excited mode of the free layer is systematically investigated. For small current values, microwave spectra due to the vortex core oscillation were observed around 1 GHz, while the frequency abruptly changed to 4-4.5 GHz at certain DC values. The experimental data were reproduced by micromagnetic simulation, which indicates that the mode change of the vortex core oscillation in the free layer is dominated by the Oersted field from the large DC.

Original language	English
Article number	052407
Journal	Applied Physics Letters
Volume	105
Issue number	5
DOIs	https://doi.org/10.1063/1.4892077
Publication status	Published - 2014 Aug 4

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10.1063/1.4892077

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title = "Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer",

abstract = "Current-induced microwave spectra were measured in small-sized giant magnetoresistance devices composed of a NiFe vortex free layer and an out-of-plane magnetized Co/Pd multilayer polarizer. The influence of a large direct current (DC) and a bias field on the excited mode of the free layer is systematically investigated. For small current values, microwave spectra due to the vortex core oscillation were observed around 1 GHz, while the frequency abruptly changed to 4-4.5 GHz at certain DC values. The experimental data were reproduced by micromagnetic simulation, which indicates that the mode change of the vortex core oscillation in the free layer is dominated by the Oersted field from the large DC.",

author = "Yuki Kawada and Hiroshi Naganuma and Demiray, {Ahmet Serdar} and Mikihiko Oogane and Yasuo Ando",

year = "2014",

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doi = "10.1063/1.4892077",

language = "English",

volume = "105",

journal = "Applied Physics Letters",

issn = "0003-6951",

publisher = "American Institute of Physics",

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Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer. / Kawada, Yuki; Naganuma, Hiroshi; Demiray, Ahmet Serdar et al.
In: Applied Physics Letters, Vol. 105, No. 5, 052407, 04.08.2014.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer

AU - Kawada, Yuki

AU - Naganuma, Hiroshi

AU - Demiray, Ahmet Serdar

AU - Oogane, Mikihiko

AU - Ando, Yasuo

PY - 2014/8/4

Y1 - 2014/8/4

N2 - Current-induced microwave spectra were measured in small-sized giant magnetoresistance devices composed of a NiFe vortex free layer and an out-of-plane magnetized Co/Pd multilayer polarizer. The influence of a large direct current (DC) and a bias field on the excited mode of the free layer is systematically investigated. For small current values, microwave spectra due to the vortex core oscillation were observed around 1 GHz, while the frequency abruptly changed to 4-4.5 GHz at certain DC values. The experimental data were reproduced by micromagnetic simulation, which indicates that the mode change of the vortex core oscillation in the free layer is dominated by the Oersted field from the large DC.

AB - Current-induced microwave spectra were measured in small-sized giant magnetoresistance devices composed of a NiFe vortex free layer and an out-of-plane magnetized Co/Pd multilayer polarizer. The influence of a large direct current (DC) and a bias field on the excited mode of the free layer is systematically investigated. For small current values, microwave spectra due to the vortex core oscillation were observed around 1 GHz, while the frequency abruptly changed to 4-4.5 GHz at certain DC values. The experimental data were reproduced by micromagnetic simulation, which indicates that the mode change of the vortex core oscillation in the free layer is dominated by the Oersted field from the large DC.

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Mode change of vortex core oscillation induced by large direct current in 120 nm sized current perpendicular-to-plane giant magnetoresistance devices with a perpendicular polarizer

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