Structural and magnetic properties of Ni 78 Fe 22 thin films sandwiched between low-softening-point glasses and application in spin devices

Takahiro Misawa, Sumito Mori, Takashi Komine, Masaya Fujioka, Junji Nishii, Hideo Kaiju

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We investigate the structural and magnetic properties of Ni 78 Fe 22 thin films sandwiched between low-softening-point (LSP) glasses, which can be used in spin quantum cross (SQC) devices utilizing stray magnetic fields generated from magnetic thin-film edges. We also calculate the stray magnetic field generated between the two edges of Ni 78 Fe 22 thin-film electrodes in SQC devices and discuss the applicability to spin-filter devices. Using the established fabrication technique, we successfully demonstrate the formation of LSP-glass/Ni 78 Fe 22 /LSP-glass structures with smooth and clear interfaces. The coercivity of the Ni 78 Fe 22 thin films is enhanced from 0.9 to 103 Oe by increasing the applied pressure from 0 to 1.0 MPa in the thermal pressing process. According to the random anisotropy model, the enhancement of the coercivity is attributed to the increase in the crystal grain size. The stray magnetic field is also uniformly generated from the Ni 78 Fe 22 thin-film edge in the direction perpendicular to the cross section of the LSP-glass/Ni 78 Fe 22 /LSP-glass structures. Theoretical calculation reveals that a high stray field of approximately 5 kOe is generated when the distance between two edges of the Ni 78 Fe 22 thin-film electrodes is less than 5 nm and the thickness of Ni 78 Fe 22 is greater than 20 nm. These experimental and calculation results indicate that Ni 78 Fe 22 thin films sandwiched between LSP glasses are useful as electrodes for SQC devices, serving as spin-filter devices.

Original languageEnglish
Pages (from-to)666-674
Number of pages9
JournalApplied Surface Science
Volume390
DOIs
Publication statusPublished - 2016 Dec 30
Externally publishedYes

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Keywords

  • Coercivity
  • Magnetic thin films
  • Micromagnetic simulation
  • Spin filter
  • Thermal pressing

ASJC Scopus subject areas

  • Surfaces, Coatings and Films

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