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 journalArticlepeer-review


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
Issue number2
Publication statusPublished - 2008 Sept 1
Externally publishedYes


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

ASJC Scopus subject areas

  • General Computer Science
  • Electrical and Electronic Engineering


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