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

Hideo Kaiju, Masashi Takei, Takahiro Misawa, Taro Nagahama, Junji Nishii, Gang Xiao

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19 Citations (Scopus)


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.

Original languageEnglish
Article number132405
JournalApplied Physics Letters
Issue number13
Publication statusPublished - 2015 Sept 28
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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