Voltage-controlled magnetic anisotropy in Fe|MgO tunnel junctions studied by x-ray absorption spectroscopy

Journal Article · Mon Oct 19 04:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4934568· OSTI ID:22485935

Miwa, Shinji; Matsuda, Kensho; Tanaka, Kazuhito; Goto, Minori; Suzuki, Yoshishige ^[1]; Kotani, Yoshinori; Nakamura, Tetsuya ^[2]

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1. Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)
2. Japan Synchrotron Radiation Research Institute/SPring-8, Sayo, Hyogo 679-5198 (Japan)

In this study, voltage-controlled magnetic anisotropy (VCMA) in Fe|MgO tunnel junctions was investigated via the magneto-optical Kerr effect, soft x-ray absorption spectroscopy, and magnetic circular dichroism spectroscopy. The Fe|MgO tunnel junctions showed enhanced perpendicular magnetic anisotropy under external negative voltage, which induced charge depletion at the Fe|MgO interface. Despite the application of voltages of opposite polarity, no trace of chemical reaction such as a redox reaction attributed to O{sup 2−} migration was detected in the x-ray absorption spectra of the Fe. The VCMA reported in the Fe|MgO-based magnetic tunnel junctions must therefore originate from phenomena associated with the purely electric effect, that is, surface electron doping and/or redistribution induced by an external electric field.

• OSTI ID: 22485935
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 16 Vol. 107; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTROSCOPY
ANISOTROPY
ELECTRIC FIELDS
ELECTRIC POTENTIAL
INTERFACES
KERR EFFECT
MAGNESIUM OXIDES
MAGNETIC CIRCULAR DICHROISM
REDOX REACTIONS
SOFT X RADIATION
SURFACES
TUNNEL EFFECT
X-RAY SPECTRA
X-RAY SPECTROSCOPY