Effects of annealing on the magnetic properties and microstructures of Ta/Mo/CoFeB/MgO/Ta films

Minghua Li*, Hui Shi, Guoqiang Yu, Jinhui Lu, Xi Chen, Gang Han, Guanghua Yu, Pedram Khalili Amiri, Kang L. Wang

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

We report a study on the evolution of perpendicular magnetic anisotropy (PMA) in Ta/Mo/CoFeB/MgO/Ta junctions annealed at 350 °C for different periods of time. The PMA quickly developed after a short annealing time followed by a slow approach to saturation. This evolution of PMA was accompanied by structural changes. The surface roughness (Rq) gradually increased with increasing annealing time to 30 min; further increases in annealing time resulted in a dramatic increase in Rq. The effects of film composition and chemical state on magnetic anisotropy in the as-deposited Ta/Mo/CoFeB/MgO/Ta films and annealed films were studied. The X-ray photoelectron spectroscopy results demonstrated that more Fe oxides were formed at the CoFeB/MgO interface after 1 min of annealing compared to in the as-deposited sample, which is critical to obtain the PMA. High-resolution transmission electron microscopy analysis revealed that the CoFeB and MgO layers are predominantly amorphous in sample as-deposited and after 1min annealing. However, the CoFeB and MgO layers are crystallized in sample after 30 and 60 min annealing, which is beneficial to get high PMA.

Original languageEnglish (US)
Pages (from-to)243-248
Number of pages6
JournalJournal of Alloys and Compounds
Volume692
DOIs
StatePublished - 2017

Keywords

  • Annealing
  • High-resolution transmission electron microscopy (HRTEM)
  • Oxygen migration
  • Perpendicular magnetic anisotropy (PMA)
  • X-ray photoelectron spectroscopy (XPS)

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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