Structural control of magnetic properties in Co/Pd multilayer for heat assisted perpendicular MRAM application

Budi Purnama, Yukio Nozaki, Kimihide Matsuyama

Research output: Contribution to journalArticle

Abstract

Temperature dependence of magnetic properties in [Co/Pd]N multilayer have been systematically studied for lithographically patterned samples with different Co thicknesses tCo and the bi-layer number N by extraordinary Hall effect measurements. The perpendicular coercive field Hc decreases with the increase of tCo, excepting a very thin thickness of 1 Å. While a threshold temperature (Tth) of Hc vanishing linearly increases with the increase of tCo. The Hc and Tth monotonously increases with the increase of N, ranged from 5 to 50. The superior crystalline structure for samples with the larger N was confirmed from enhanced Co/Pd(111) peak height in the XRD pattern. A practical thermal activation coefficient α of 174 was evaluated from a sweep rate dependence of Hc. A marked improvements for the heat assisted MRAM application was attained by air annealing of [Co(1.7 Å)Pd(8 Å)]30 at 220°t, that is, the Hc was increased from 1.3 kOe to 2.9 kOe, while Tth reduced from 210°C to 190°C.

Original languageEnglish
Pages (from-to)75-79
Number of pages5
JournalResearch Reports on Information Science and Electrical Engineering of Kyushu University
Volume13
Issue number2
Publication statusPublished - 2008 Sep
Externally publishedYes

Fingerprint

Magnetic properties
Multilayers
Hall effect
Chemical activation
Annealing
Crystalline materials
Temperature
Air
Hot Temperature

Keywords

  • Extra ordinary Hall resistance
  • Magnetic multilayer
  • Magnetic random access memory
  • Perpendicular magnetic anisotropy
  • Thermally assisted magnetization reversal

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Science(all)

Cite this

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title = "Structural control of magnetic properties in Co/Pd multilayer for heat assisted perpendicular MRAM application",
abstract = "Temperature dependence of magnetic properties in [Co/Pd]N multilayer have been systematically studied for lithographically patterned samples with different Co thicknesses tCo and the bi-layer number N by extraordinary Hall effect measurements. The perpendicular coercive field Hc decreases with the increase of tCo, excepting a very thin thickness of 1 {\AA}. While a threshold temperature (Tth) of Hc vanishing linearly increases with the increase of tCo. The Hc and Tth monotonously increases with the increase of N, ranged from 5 to 50. The superior crystalline structure for samples with the larger N was confirmed from enhanced Co/Pd(111) peak height in the XRD pattern. A practical thermal activation coefficient α of 174 was evaluated from a sweep rate dependence of Hc. A marked improvements for the heat assisted MRAM application was attained by air annealing of [Co(1.7 {\AA})Pd(8 {\AA})]30 at 220°t, that is, the Hc was increased from 1.3 kOe to 2.9 kOe, while Tth reduced from 210°C to 190°C.",
keywords = "Extra ordinary Hall resistance, Magnetic multilayer, Magnetic random access memory, Perpendicular magnetic anisotropy, Thermally assisted magnetization reversal",
author = "Budi Purnama and Yukio Nozaki and Kimihide Matsuyama",
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TY - JOUR

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AU - Purnama, Budi

AU - Nozaki, Yukio

AU - Matsuyama, Kimihide

PY - 2008/9

Y1 - 2008/9

N2 - Temperature dependence of magnetic properties in [Co/Pd]N multilayer have been systematically studied for lithographically patterned samples with different Co thicknesses tCo and the bi-layer number N by extraordinary Hall effect measurements. The perpendicular coercive field Hc decreases with the increase of tCo, excepting a very thin thickness of 1 Å. While a threshold temperature (Tth) of Hc vanishing linearly increases with the increase of tCo. The Hc and Tth monotonously increases with the increase of N, ranged from 5 to 50. The superior crystalline structure for samples with the larger N was confirmed from enhanced Co/Pd(111) peak height in the XRD pattern. A practical thermal activation coefficient α of 174 was evaluated from a sweep rate dependence of Hc. A marked improvements for the heat assisted MRAM application was attained by air annealing of [Co(1.7 Å)Pd(8 Å)]30 at 220°t, that is, the Hc was increased from 1.3 kOe to 2.9 kOe, while Tth reduced from 210°C to 190°C.

AB - Temperature dependence of magnetic properties in [Co/Pd]N multilayer have been systematically studied for lithographically patterned samples with different Co thicknesses tCo and the bi-layer number N by extraordinary Hall effect measurements. The perpendicular coercive field Hc decreases with the increase of tCo, excepting a very thin thickness of 1 Å. While a threshold temperature (Tth) of Hc vanishing linearly increases with the increase of tCo. The Hc and Tth monotonously increases with the increase of N, ranged from 5 to 50. The superior crystalline structure for samples with the larger N was confirmed from enhanced Co/Pd(111) peak height in the XRD pattern. A practical thermal activation coefficient α of 174 was evaluated from a sweep rate dependence of Hc. A marked improvements for the heat assisted MRAM application was attained by air annealing of [Co(1.7 Å)Pd(8 Å)]30 at 220°t, that is, the Hc was increased from 1.3 kOe to 2.9 kOe, while Tth reduced from 210°C to 190°C.

KW - Extra ordinary Hall resistance

KW - Magnetic multilayer

KW - Magnetic random access memory

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KW - Thermally assisted magnetization reversal

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