Large magnetocapacitance effect in magnetic tunnel junctions based on Debye-Fröhlich model

Journal Article · Mon Sep 28 04:00:00 UTC 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4932093· OSTI ID:22482171

Kaiju, Hideo; Takei, Masashi; Misawa, Takahiro; Nishii, Junji ^[1]; Nagahama, Taro ^[2]; Xiao, Gang ^[3]

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1. Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0020 (Japan)
2. School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan)
3. Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)

The frequency dependence of tunneling magnetocapacitance (TMC) in magnetic tunnel junctions (MTJs) is investigated theoretically and experimentally. According to the calculation based on Debye-Fröhlich model combined with Julliere formula, the TMC ratio strongly depends on the frequency and it has the maximum peak at a specific frequency. The calculated frequency dependence of TMC is in good agreement with the experimental results obtained in MgO-based MTJs with a tunneling magnetoresistance (TMR) ratio of 108%, which exhibit a large TMC ratio of 155% at room temperature. This calculation also predicts that the TMC ratio can be as large as about 1000% for a spin polarization of 87%, while the TMR ratio is 623% for the same spin polarization. These theoretical and experimental findings provide a deeper understanding on AC spin-dependent transport in the MTJs and will open up wider opportunities for device applications, such as highly sensitive magnetic sensors and impedance-tunable devices.

• OSTI ID: 22482171
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 13 Vol. 107; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
FREQUENCY DEPENDENCE
IMPEDANCE
MAGNESIUM OXIDES
MAGNETORESISTANCE
SENSORS
SPIN
SPIN ORIENTATION
TEMPERATURE RANGE 0273-0400 K
TUNNEL EFFECT