Microwave-Assisted switching in CoCrPt granular medium under continuous microwave fields

Nobuaki Kikuchi; Katsunari Sato; Shun Kikuchi; Satoshi Okamoto; Takehito Shimatsu; Osamu Kitakami; Hitoshi Osawa; Motohiro Suzuki

doi:10.1063/1.5111576

Microwave-Assisted switching in CoCrPt granular medium under continuous microwave fields

Nobuaki Kikuchi, Katsunari Sato, Shun Kikuchi, Satoshi Okamoto, Takehito Shimatsu, Osamu Kitakami, Hitoshi Osawa, Motohiro Suzuki

Research output: Contribution to journal › Article › peer-review

7 Citations (Scopus)

Abstract

We have fabricated a device for microwave-Assisted switching (MAS) experiments with perpendicularly magnetized CoCrPt-SiO₂ granular film with anisotropy field H_k = 18.8 kOe. The device was carefully designed to be able to apply a microwave field of 0.95 kOe in amplitude continuously, allowing direct evaluation of microwave-Assisted switching properties of the medium without any assumptions about time-dependent switching behavior. The coercivity of CoCrPt-SiO₂ medium linearly decreases with increasing microwave frequency, and the maximum coercivity reduction ratio reaches 80% for h_rf = 0.95 kOe at f_rf = 25 GHz after subtracting the effect of temperature rise due to microwave field application. The linear slope of coercivity against the frequency becomes steeper with increasing microwave field amplitude, which is a unique frequency and amplitude dependencies in granular media. Correlation length obtained by X-ray magnetic circular dichroism microscopy measurement decreases by applying a microwave field with higher frequency, suggesting that the magnetic clustering dimensions of the medium possibly depend on microwave frequency during microwave-Assisted switching.

Original language	English
Article number	083908
Journal	Journal of Applied Physics
Volume	126
Issue number	8
DOIs	https://doi.org/10.1063/1.5111576
Publication status	Published - 2019 Aug 28

ASJC Scopus subject areas

Physics and Astronomy(all)

Access to Document

10.1063/1.5111576

Cite this

@article{d4925ab1e4854441bbdb894569f3af6c,

title = "Microwave-Assisted switching in CoCrPt granular medium under continuous microwave fields",

abstract = "We have fabricated a device for microwave-Assisted switching (MAS) experiments with perpendicularly magnetized CoCrPt-SiO2 granular film with anisotropy field Hk = 18.8 kOe. The device was carefully designed to be able to apply a microwave field of 0.95 kOe in amplitude continuously, allowing direct evaluation of microwave-Assisted switching properties of the medium without any assumptions about time-dependent switching behavior. The coercivity of CoCrPt-SiO2 medium linearly decreases with increasing microwave frequency, and the maximum coercivity reduction ratio reaches 80% for hrf = 0.95 kOe at frf = 25 GHz after subtracting the effect of temperature rise due to microwave field application. The linear slope of coercivity against the frequency becomes steeper with increasing microwave field amplitude, which is a unique frequency and amplitude dependencies in granular media. Correlation length obtained by X-ray magnetic circular dichroism microscopy measurement decreases by applying a microwave field with higher frequency, suggesting that the magnetic clustering dimensions of the medium possibly depend on microwave frequency during microwave-Assisted switching.",

author = "Nobuaki Kikuchi and Katsunari Sato and Shun Kikuchi and Satoshi Okamoto and Takehito Shimatsu and Osamu Kitakami and Hitoshi Osawa and Motohiro Suzuki",

note = "Funding Information: This work was partly supported by JSPS KAKENHI (Nos. 17K05028 and 17H03227), Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials from MEXT, and ASRC. The synchrotron radiation experiments were carried out at SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) as SPring-8 Epoch-Making Initiatives Projects (Initiative study for nano-spin devices led by the use of advanced synchrotron light source, Proposal Nos. 2017A0902, 2017B0931, 2018A0931, and 2018B0931). Publisher Copyright: {\textcopyright} 2019 Author(s).",

year = "2019",

month = aug,

day = "28",

doi = "10.1063/1.5111576",

language = "English",

volume = "126",

journal = "Journal of Applied Physics",

issn = "0021-8979",

publisher = "American Institute of Physics Publising LLC",

number = "8",

}

TY - JOUR

T1 - Microwave-Assisted switching in CoCrPt granular medium under continuous microwave fields

AU - Kikuchi, Nobuaki

AU - Sato, Katsunari

AU - Kikuchi, Shun

AU - Okamoto, Satoshi

AU - Shimatsu, Takehito

AU - Kitakami, Osamu

AU - Osawa, Hitoshi

AU - Suzuki, Motohiro

N1 - Funding Information: This work was partly supported by JSPS KAKENHI (Nos. 17K05028 and 17H03227), Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials from MEXT, and ASRC. The synchrotron radiation experiments were carried out at SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) as SPring-8 Epoch-Making Initiatives Projects (Initiative study for nano-spin devices led by the use of advanced synchrotron light source, Proposal Nos. 2017A0902, 2017B0931, 2018A0931, and 2018B0931). Publisher Copyright: © 2019 Author(s).

PY - 2019/8/28

Y1 - 2019/8/28

N2 - We have fabricated a device for microwave-Assisted switching (MAS) experiments with perpendicularly magnetized CoCrPt-SiO2 granular film with anisotropy field Hk = 18.8 kOe. The device was carefully designed to be able to apply a microwave field of 0.95 kOe in amplitude continuously, allowing direct evaluation of microwave-Assisted switching properties of the medium without any assumptions about time-dependent switching behavior. The coercivity of CoCrPt-SiO2 medium linearly decreases with increasing microwave frequency, and the maximum coercivity reduction ratio reaches 80% for hrf = 0.95 kOe at frf = 25 GHz after subtracting the effect of temperature rise due to microwave field application. The linear slope of coercivity against the frequency becomes steeper with increasing microwave field amplitude, which is a unique frequency and amplitude dependencies in granular media. Correlation length obtained by X-ray magnetic circular dichroism microscopy measurement decreases by applying a microwave field with higher frequency, suggesting that the magnetic clustering dimensions of the medium possibly depend on microwave frequency during microwave-Assisted switching.

AB - We have fabricated a device for microwave-Assisted switching (MAS) experiments with perpendicularly magnetized CoCrPt-SiO2 granular film with anisotropy field Hk = 18.8 kOe. The device was carefully designed to be able to apply a microwave field of 0.95 kOe in amplitude continuously, allowing direct evaluation of microwave-Assisted switching properties of the medium without any assumptions about time-dependent switching behavior. The coercivity of CoCrPt-SiO2 medium linearly decreases with increasing microwave frequency, and the maximum coercivity reduction ratio reaches 80% for hrf = 0.95 kOe at frf = 25 GHz after subtracting the effect of temperature rise due to microwave field application. The linear slope of coercivity against the frequency becomes steeper with increasing microwave field amplitude, which is a unique frequency and amplitude dependencies in granular media. Correlation length obtained by X-ray magnetic circular dichroism microscopy measurement decreases by applying a microwave field with higher frequency, suggesting that the magnetic clustering dimensions of the medium possibly depend on microwave frequency during microwave-Assisted switching.

UR - http://www.scopus.com/inward/record.url?scp=85071655181&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85071655181&partnerID=8YFLogxK

U2 - 10.1063/1.5111576

DO - 10.1063/1.5111576

M3 - Article

AN - SCOPUS:85071655181

VL - 126

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 8

M1 - 083908

ER -

Microwave-Assisted switching in CoCrPt granular medium under continuous microwave fields

Abstract

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this