Nanostructure and magnetic properties of c -axis oriented L 10 -FePt nanoparticles and nanocrystalline films on polycrystalline TiN underlayers

Yoshiko Tsuji, Suguru Noda, Shinichi Nakamura

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We performed a systematic study of the nanostructure and magnetic properties of FePt on templates of either (200)-oriented polycrystalline TiN underlayers with in-plane grain sizes from 5.8 to 10 nm (poly-TiN) or highly (200)-textured TiN underlayers epitaxially grown on single-crystalline MgO (100) substrates (epi-TiN). For small nominal FePt thicknesses (0.7-8.0 nm), FePt forms particulate films with the magnetic easy axis perpendicular to the film plane on every template TiN underlayer. In addition, the coercivity of nominally 1.4-nm-thick FePt at 300 K in the out-of-plane direction increases from 5.3 kOe for 5.8-nm-sized poly-TiN to 12.9 kOe for 10-nm-sized poly-TiN and reaches 16.3 kOe for epi-TiN, which shows that the coercivity strongly depends on the degree of the c -axis orientation. For larger FePt nominal thicknesses (16-64 nm), FePt particles percolate and form continuous films, and the direction of the easy magnetic easy axis becomes random. The coercivity of nominally 64-nm-thick FePt at 300 K in the out-of-plane direction is still as large as 8.8 kOe for 10-nm-sized poly-TiN, but it drastically decreases to 0.5 kOe for epi-TiN. The absence of in-plane texture in the FePt layer on the poly-TiN suppresses the decrease in coercivity, which prevents domain-wall displacement.

Original languageEnglish
Article number031801
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Volume29
Issue number3
DOIs
Publication statusPublished - 2011 May
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry

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