Interfacial Perpendicular Magnetic Anisotropy in Magnetic Tunnel Junctions Comprising CoFeB with FeNiSiB Layers

Do Kyun Kim, Minhyeok Lee, Junghoon Joo, Young Keun Kim

Research output: Contribution to journalArticle

Abstract

Abstract: Controlling ferromagnetic thickness (t) and properties such as saturation magnetization (Ms) and effective magnetic anisotropy constant (Keff) has been regarded as critical for the performance of magnetic tunnel junctions (MTJs) with interfacial perpendicular magnetic anisotropy. Here, we report the effects of hybridizing a CoFeB layer with a FeNiSiB layer as part of a magnetic free layer structure. We deposited thin film stacks by magnetron sputtering on Si wafers with thermal oxides and carried out post-deposition heat treatment at 300 °C for 1 h in a vacuum under a magnetic field. We found that Ms and Keff could be tuned by adding a layer of amorphous FeNiSiB. While the Ms and Keff values were modified, the tunneling magnetoresistance (TMR) ratios of the MTJs were maintained, even though the CoFeB thickness was decreased by half. Moreover, an asymmetric bias voltage dependence of TMR was suppressed in the MTJs with FeNiSiB/CoFeB hybrid free layers due to improvements in the interface quality between the CoFeB/MgO interfaces. Graphic Abstract: [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)35-40
Number of pages6
JournalElectronic Materials Letters
Volume16
Issue number1
DOIs
Publication statusPublished - 2020 Jan 1

Keywords

  • CoFeB
  • FeNiSiB
  • Hybrid free layer
  • Magnetic tunnel junction
  • Perpendicular magnetic anisotropy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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