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

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.
Authors:
; ; ;  [1] ;  [2] ;  [3]
  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)
Publication Date:
OSTI Identifier:
22482171
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 13; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; FREQUENCY DEPENDENCE; IMPEDANCE; MAGNESIUM OXIDES; MAGNETORESISTANCE; SENSORS; SPIN; SPIN ORIENTATION; TEMPERATURE RANGE 0273-0400 K; TUNNEL EFFECT