TY - JOUR
T1 - Tunnel magnetocapacitance in Fe/MgF2 single nanogranular layered films
AU - Msiska, Robin
AU - Honjo, Shusaku
AU - Asai, Yuki
AU - Arita, Masashi
AU - Tsurumaki-Fukuchi, Atsushi
AU - Takahashi, Yasuo
AU - Hoshino, Norihisa
AU - Akutagawa, Tomoyuki
AU - Kitakami, Osamu
AU - Fujioka, Masaya
AU - Nishii, Junji
AU - Kaiju, Hideo
N1 - Funding Information:
This research was supported and made possible by the Japan Society for the Promotion of Science (JSPS) KAKENHI (Nos. 15H01706, 16H04339, 16K18073, 17K19019, 18H01485, and 19K22093); the Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials; the Cooperative Research Project of the Research Center of Biomedical Engineering and the Cooperative Research Program of the “Network Joint Research Center for Materials and Devices” funded by the Ministry of Education, Culture, Sports, Science, and Technology (MEXT); and the Research Project funded by the Center for Spintronics Research Network (CSRN) at Tohoku and Keio University.
Publisher Copyright:
© 2020 Author(s).
PY - 2020/2/24
Y1 - 2020/2/24
N2 - The tunnel magnetocapacitance (TMC) effect in two-dimensional single nanogranular layered Fe / MgF 2 films is investigated both experimentally and theoretically. We measured the frequency dependence of TMC ratios in a frequency range of 20 Hz-1 MHz and discovered that TMC ratios strongly depend on the frequency, reaching a peak value at a specific frequency. We observe that the largest TMC ratios occur at lower frequencies and that TMC values steadily reduce with increasing frequency. Notably, we achieved a maximum TMC ratio of 1.45%, which is the largest low-field TMC ever reported for granular films. A combination of the Debye-Fröhlich (DF) model and the Julliere formula is used to fit the experimental data to theory, and an excellent agreement between the calculated values and the experimental data is obtained. To perfectly fit the experimental data, the conventional DF model is extended to a composite model in which three capacitors (with three different relaxation times) are introduced. Our findings will give further insights into the exact mechanism of the TMC effect in nanogranular films and will open broader opportunities for device applications, such as magnetic sensors and impedance tunable devices.
AB - The tunnel magnetocapacitance (TMC) effect in two-dimensional single nanogranular layered Fe / MgF 2 films is investigated both experimentally and theoretically. We measured the frequency dependence of TMC ratios in a frequency range of 20 Hz-1 MHz and discovered that TMC ratios strongly depend on the frequency, reaching a peak value at a specific frequency. We observe that the largest TMC ratios occur at lower frequencies and that TMC values steadily reduce with increasing frequency. Notably, we achieved a maximum TMC ratio of 1.45%, which is the largest low-field TMC ever reported for granular films. A combination of the Debye-Fröhlich (DF) model and the Julliere formula is used to fit the experimental data to theory, and an excellent agreement between the calculated values and the experimental data is obtained. To perfectly fit the experimental data, the conventional DF model is extended to a composite model in which three capacitors (with three different relaxation times) are introduced. Our findings will give further insights into the exact mechanism of the TMC effect in nanogranular films and will open broader opportunities for device applications, such as magnetic sensors and impedance tunable devices.
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U2 - 10.1063/1.5139702
DO - 10.1063/1.5139702
M3 - Article
AN - SCOPUS:85080147464
SN - 0003-6951
VL - 116
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 8
M1 - 082401
ER -