Effects of substrate surface topology on NiFe/Cu/Co spin valve characteristics

Hyeong Jun Kim, Won Cheol Jeong, Kwon Ku Cho, Young Keun Kim, Seung Ki Joo

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In order to control the crystallinity of sputter-deposited NiFe/Cu/Co spin valve thin films, surface topology of 4°tilt-cut Si(111) substrates was modified in various ways prior to formation of the spin valves. In case of the mirror polished substrate, NiFe and Co showed fcc (110) preferred orientation with in-plane uniaxial magnetic anisotropy. The easy axes of these magnetic layers were aligned in 90° to each other and giant magnetoresistance (GMR) was measured to be 4.5% at room temperature. The spin valves formed on the amorphized substrate by Ar ion mass doping, however, did not show magnetic anisotropy due to the loss of crystallinity and no appreciable GMR could be observed. The spin valves deposited on the unpolished substrate, of which the average surface roughness was measured to be a few microns, turned out to show a sound multilayeredness as well as crystallinity, but GMR was reduced to 3.5%. Tailing in the magnetoresistance (R-H) curve occurred in the spin valves formed on the unpolished substrate, and it was thought to be attributed to the shape anisotropy related to the interface roughness of the films. Detailed discussion on the relationship between GMR and crystallinity of the magnetic layers has been made with the results of simple simulation.

Original languageEnglish
Pages (from-to)4767-4771
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume39
Issue number8
Publication statusPublished - 2000 Aug

ASJC Scopus subject areas

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

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