Research Achievements - Original paper -

Investigation of Substitution of Nickel Cations in Cobalt Ferrite (CoFe<inf>2</inf>O<inf>4</inf>) Nanoparticles and Their Influence on Frequency and Temperature Dependent Dielectric and Magnetodielectric Properties

B. Dash, K. L. Routray, S. Saha, S. Yoshimura, S. Ratha, M. K. Rout

Transactions on Electrical and Electronic Materials ( Transactions on Electrical and Electronic Materials )  25 ( 2 ) 232 - 246   2024.03  [Refereed]

Research paper (journal)   International Co-author

DOI

Structural, magnetic and dielectric properties of green synthesized Ag doped NiFe<inf>2</inf>O<inf>4</inf> spinel ferrite

Sunirmal Saha, Krutika Routray, Pritish. Hota, Biswajita Dash, Satoru Yoshimura, Soumyaranjan Ratha, and Traibhab Kumar Nayak

Journal of Molecular Structure ( Journal of Molecular Structure )  1302   2024.03  [Refereed]

Research paper (journal)   International Co-author

DOI

Optimizing the reactive ion etching conditions with minimal damage for high functional magnetic nano device application in BiFeO<inf>3</inf>-based thin film by Eu/Co substitution

S. Ratha, G. Egawa, S. Yoshimura

Applied Surface Science ( Applied Surface Science )  643   158704   2024.01  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Investigation of Fabrication Conditions and Acceleration of Crystallization of α"-Fe₁₆N₂ Thin Film Fabricated by Pulsed DC Reactive Sputtering for High Density Magnetic Recording Media Application

Ikuko KATSUYAMA, Genta EGAWA, Satoru YOSHIMURA

Journal of the Society of Materials Engineering for Resources of Japan ( The Society of Materials Engineering for Resources of JAPAN )  34 ( 0 ) 6 - 14   2024.01  [Refereed]

Research paper (journal)   Domestic Co-author

DOI CiNii Research

Analysis of substitution of bismuth cations in CoFe<inf>2</inf>O<inf>4</inf> nanoparticles and their influence on frequency and temperature-dependent dielectric and magnetodielectric properties

Biswajita Dash, Sunirmal Saha, Satoru Yoshimura, Soumyaranjan Ratha, and Jashashree Ray

Journal of Materials Science: Materials in Electronics ( Journal of Materials Science: Materials in Electronics )  34 ( 36 )   2023.12  [Refereed]

Research paper (journal)   International Co-author

DOI

Magnetization reversal of [Co/Pd] perpendicular magnetic thin film dot on (Bi,La)(Fe,Co)O<inf>3</inf>multiferroic thin film by applying electric field

Satoru Yoshimura, Naoya Oshita, Genta Egawa, and Munusamy Kuppan

Nanotechnology ( Nanotechnology )  34 ( 46 ) 465703   2023.08  [Refereed]  [Invited]

Research paper (journal)   Domestic Co-author

DOI

Synergistic Effect of Allium-like Ni9S8 & Cu7S4 Electrodeposited on Nickel Foam for Enhanced Water Splitting Activity

M. Mottakin, V. Selvanathan, Md. A. Islam, H. Almohamadi, N. H. Alharthi, S. Yoshimura, Md. Akhtaruzzaman

Chemistry - An Asian Journal ( Chemistry - An Asian Journal )    e202300532   2023.08  [Refereed]

Research paper (journal)   International Co-author

DOI

Excellent magnetic properties in multiferroic BiFeO3 based thin films for magnetic devices application

Soumyaranjan Ratha, Munusamy Kuppan, Genta Egawa, Satoru Yoshimura

Nano-Structures & Nano-Objects ( Elsevier )  35   101007   2023.07  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Facile electrodeposition of biphasic CuSx/CoSx nanostructures as bifunctional electrocatalysts for seawater splitting

M. Mottakin, Vidhya Selvanathan, Syaza Amira Razali, Md. Ariful Islam, Hamad Almohamadi, Nabeel H. Alharthi, Satoru Yoshimura, Md. Akhtaruzzaman

Electrochimica Acta ( Elsevier )  463   142861   2023.07  [Refereed]

Research paper (journal)   International Co-author

DOI

Effects of substituted elements and amounts of B-site on magnetic properties of ferromagnetic and ferroelectric (Bi,La)(Fe1-yMy)O3 (M=Ni,Co) thin films

SUZUKI Yuta, OZEKI Takumi, EGAWA Genta, YOSHIMURA Satoru

Journal of the Society of Materials Engineering for Resources of Japan ( The Society of Materials Engineering for Resources of JAPAN )  33 ( 1_2 ) 12 - 17   2023.04  [Refereed]

Research paper (journal)   Domestic Co-author

CiNii Research

Development of (Bi0.5L 0.5)(Fe0.7Co0.3)O3 (L=La, Nd, Sm, Gd, Dy) Tthin Films with Excellent Magnetic Properties for Magnetic Device Application

S. Ratha, D. Yamamoto, K. Takeda, M. Kuppan, G. Egawa, and S. Yoshimura

International Journal of the Society of Materials Engineering for Resources ( 日本素材物性学会 )  25 ( 2 ) 174 - 178   2022.10  [Refereed]

Research paper (journal)   Domestic Co-author

<p>(Bi_0.5<i>L</i>_0.5)(Fe_0.7Co_0.3)O₃ (<i>L </i>=<i> </i>La, Nd, Sm, Gd, Dy) thin films with ferromagnetism and ferroelectricity were fabricated using pulsed DC sputtering technique to obtain high saturation magnetization, perpendicular magnetic anisotropy and large magnetic Kerr effect. These magnetic properties are very important for realization of high performance magnetic devices driven by electric field. All (Bi_0.5<i>L</i>_0.5)(Fe_0.7Co_0.3)O₃ (<i>L </i>=<i> </i>La, Nd, Sm, Gd, Dy) thin films had relatively high saturation magnetization, perpendicular magnetic anisotropy and magnetic Kerr effect. Especially, (Bi_0.5Nd_0.5)(Fe_0.7Co_0.3)O₃ thin film had a very high saturation magnetization of 140 emu/cm³ (1.40×10⁵ A/m), a high perpendicular magnetic anisotropy of 2.6 at ratio of perpendicular coercivity against in-plane coercivity and (Bi_0.5La_0.5)(Fe_0.7Co_0.3)O₃ thin film had a very high magnetic Kerr rotation angle of 0.72°. These magnetic properties were excellent compared with the case of (Bi_0.5<i>A</i>_0.5)FeO₃ (<i>A </i>=<i> </i>Ca, Sr, Ba) thin films with the maximum value of 90 emu/cm³ (9.0×10⁴ A/m) (for saturation magnetization), 0.8 (for ratio of Perpendicular coercivity against in-plane coercivity) and 0.03° (for magnetic Kerr rotation angle) which were fabricated previously. These magnetic properties are very important for realization of high performance magnetic devices driven by electric field.</p>

DOI CiNii Research

Investigations on Spintronic RFeO₃ Crystals Grown by Optical Floating Zone Technique

P. Ramesh Babu, S. Kalainathan, and S. Yoshimura

International Journal of the Society of Materials Engineering for Resources ( 日本素材物性学会 )  25 ( 2 ) 179 - 182   2022.10  [Refereed]  [Invited]

Research paper (journal)   International Co-author

<p>Magnetic crystals are physically important to know their intrinsic magnetic properties. Magnetic crystals are also technologically important and their creation has aided crystal growth significantly. Rareearth orthoferrites material (RFeO₃) is one of the major components used in manufacturing sophisticated gadgets. This study focuses on the growth and physical properties of the optically generated RFeO₃ (R=Y, Gd and Sm) single crystals. The floating zone method generates single crystals of 3-20 mm/h in the optical zone. The purity of the grown materials was confirmed from the Powder X-Ray Diffraction (PXRD) analysis. The addition of Gd to YFeO₃ increases the lattice parameters of the material. Magnetic properties of the grown crystal were studied between 20-700 K. At high temperature, two anomalous effects were observed, one at (T_SR=480 K) due to spin reorientation and the other is antiferromagnetic (AFM) to paramagnetic transitions at (T_N= 670 K). Bloch parameter was also calculated. Microhardness value decreases nonlinearly. When the applied load is greater than 1.96 N, there is a transition from palmqvist to median crack due to the plastic deformation of the crystal. Controllable magnetic and mechanical characteristics will help to enhance performance of magnetic devices.</p>

DOI CiNii Research

Development of BiFeO3-based multiferroic thin films with large saturation magnetization and perpendicular magnetic anisotropy -The effect of the Co substitution against Fe on magnetic properties-

T. Ozeki, D. Yamamoto, G. Egawa, and S. Yoshimura

Journal of the Magnetics Society of Japan ( 日本磁気学会 )  46 ( 3 ) 64 - 69   2022.05  [Refereed]

Research paper (journal)   Domestic Co-author

<p>  High saturation magnetization and perpendicular magnetic anisotropy are required for ferromagnetic / ferroelectric thin films to apply magnetic recording such as magnetic writing elements of magnetic wire memory, which is a next-generation device with very high recording density. To realize the magnetic properties, substitution of Co against Fe in (Bi_1-xBax)FeO₃ and (Bi_1-xLa_x)FeO₃ thin films were investigated. In the (Bi,Ba)(Fe,Co)O₃ thin films, both Ba and Co substitution up to several tens at% had contribution to increase the saturation magnetization. The high saturation magnetization was obtained in (Bi,Ba)(Fe,Co)O₃ thin films with the total composition of Ba and Co of around 60 at%. Further increment of Ba and Co substitution decreased the saturation magnetization because the formation of the BiFeO₃ phase is hindered by an excess amount of Ba and Co with larger ion radius than Bi and Fe. Co substitution up to 20 at% had contribution to increase the perpendicular magnetic anisotropy. In the (Bi,La)(Fe,Co)O₃ thin films, the effect of La substitution was not large to increase the saturation magnetization and perpendicular magnetic anisotropy, however the effect of Co substitution up to 30 at% was large to increase the saturation magnetization and perpendicular magnetic anisotropy.</p>

DOI CiNii Research

Dependence of magnetic properties in superparamagnetic Co-granular thin films on deposition rate and effectiveness of a new pulsed DC reactive sputtering method for film fabrication with high deposition rate.

KOBAYASHI Takumi, NAKADA Akito, EGAWA Genta, YOSHIMURA Satoru

Journal of the Society of Materials Engineering for Resources of Japan ( The Society of Materials Engineering for Resources of JAPAN )  32 ( 1_2 ) 22 - 27   2022.03  [Refereed]

Research paper (journal)   Domestic Co-author

DOI CiNii Research

Effect of laser-assisted heating and annealing on the crystal structure and magnetic properties of(Bi, <i>A</i>)FeO₃(<i>A</i>=Ca, Sr, Ba(alkaline earth metal)) thin films

SUZUKI Riku, OZEKI Takumi, EGAWA Genta, YOSHIMURA Satoru

Journal of the Society of Materials Engineering for Resources of Japan ( The Society of Materials Engineering for Resources of JAPAN )  32 ( 1_2 ) 15 - 21   2022.03  [Refereed]

Research paper (journal)   Domestic Co-author

DOI CiNii Research

High-resolution alternating magnetic force microscopy using an amorphous FeB-based tip driven by an inverse magnetostrictive effect: imaging of the high-density magnetic recording media

M. V. Makarova, Y. Akaishi, Y. Suzuki, K. S. Rao, S. Yoshimura, H. Saito

Journal of Magnetism and Magnetic Materials ( Journal of Magnetism and Magnetic Materials )  546 ( 10 ) 168755   2022.01  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Magnetic properties of (Bi1−xLax)(Fe,Co)O3 films fabricated by a pulsed DC reactive sputtering and demonstration of magnetization reversal by electric field

Munusamy Kuppan, Daichi Yamamoto, Genta Egawa, Sivaperuman Kalainathan, Satoru Yoshimura

Scientific Reports ( Scientific Reports )  11   11118-1 - 11118-8   2021.05  [Refereed]

Research paper (journal)   International Co-author

DOI

Guidelines for fabrication of high quality BiFeO₃ based multiferroic thin films in pulsed DC reactive sputtering method

Takeda K., Yamamoto D., Yoshimura S.

Transaction of the Magnetics Society of Japan Special Issues ( The Magnetics Society of Japan )  4 ( 2 ) 116 - 120   2020.09  [Refereed]

Research paper (journal)   Domestic Co-author

<p>  BiFeO₃ based thin films with ferromagnetism were fabricated by using a pulsed DC reactive sputtering method. Guidelines on sputtering targets for fabricating the films are discussed in regard to obtaining high-quality BiFeO₃ based thin films. By using a target with a low oxide content (low molar ratio of oxide) and thus good conductivity, it is possible to suppress the charging and arc discharge on the surface of the target and enable high-energy sputtering. As a result, high-quality BiFeO₃ based thin films with a high saturation magnetization were formed. By using a target with a high oxygen content (including oxides with a high oxidation valence), the generation of oxygen vacancies that degrade the ferroelectric properties is suppressed, and pinning sites that suppress domain wall movement are then also suppressed. As a result, high-quality BiFeO₃ based thin films with good ferromagnetic properties could be formed.</p>

DOI CiNii Research

Alternating Magnetic Force Microscopy: Effect of Si doping on the temporal performance degradation of amorphous FeCoB magnetic tips

Makarova, Y. Akaishi, T. Ikarashi, K. S. Rao, S. Yoshimura, and H. Saito

Journal of Magnetism and Magnetic Materials ( Journal of Magnetism and Magnetic Materials )  471   209 - 214   2019.02  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

High coercivity and resolution FePt•MgO-coated tip for imaging the magnetic field of perpendicular magnetic write head by alternating magnetic force microscopy (A-MFM)

Fu Zheng, Satoru Yoshimura, Shinya Yasui, Genta Egawa, and Hitoshi Saito

Journal of the Magnetics Society of Japan ( Journal of the Magnetics Society of Japan )  43 ( 1 ) 6 - 10   2019.01  [Refereed]

Research paper (journal)   Domestic Co-author

<p>  High coercivity FePt•MgO films were successfully synthetized on cone-shape Si tips in a very high frequency (VHF) plasma irradiation-assisted magnetron sputtering system to prepare the MFM tips for evaluation of the AC magnetic field of perpendicular magnetic write head at high write current. Alloying with MgO significantly enhanced the coercivity of the magnetic coating due to the isolation of FePt grains by MgO. As a result, a high coercivity close to 20 kOe was achieved. The AC magnetic field images of the perpendicular magnetic write head at high write current were taken on alternating MFM (A-MFM) by this tip. A clear amplitude image with a strong signal at the main pole position was observe compared to the pure FePt layer-coated tip, which gave a blurry image and very small amplitude. Fourier analysis of the images obtained by this kind of FePt•MgO tip gives a spatial resolution of about 15 nm in air atmosphere. It is clear that the cone-shape FePt•MgO-coated MFM tip with a coercivity higher than the magnetic field to be measured is effective and capable for measuring the high AC magnetic field for an HD perpendicular magnetic write head at a very high write current.</p>

DOI CiNii Research

High magnetization Co-GdOx superparamagnetic granular films as magnetic coating materials for high-sensitivity alternating magnetic force microscopy tip

Yongze Cao, Pawan Kumar, Yue Zhao, Yudai Suzuki, Satoru Yoshimura, Hitoshi Saito

Journal of Magnetism and Magnetic Materials ( Journal of Magnetism and Magnetic Materials )  462   119 - 126   2018.09  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Fabrication of high-qualified (Bi1-xBax)FeO3 multiferroic thin films by using a pulsed DC reactive sputtering method and demonstration of magnetization reversal by electric field

Satoru Yoshimura, Munusamy Kuppan

Japanese Journal of Applied Physics ( Japanese Journal of Applied Physics )  57 ( 9 )   2018.09  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Magnetic energy flow imaging of magnetic recording head with enhanced resolution and sensitivity by A-MFM using high magnetic moment superparamagnetic tip

Pawan Kumar, Yongze Cao, Yudai Suzuki, Satoru Yoshimura, and Hitoshi Saito

Journal of Applied Physics ( Journal of Applied Physics )  123 ( 21 ) 214503   2018.06  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Magnetic domain imaging of a very rough fractured surface of Sr ferrite magnet without topographic crosstalk by alternating magnetic force microscopy with a sensitive FeCo-GdOx superparamagnetic tip

Yongze Cao, Yue Zhao, Pawan Kumar, Satoru Yoshimura, and Hitoshi Saito

Journal of Applied Physics ( Journal of Applied Physics )  123 ( 22 ) 224503   2018.06  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Active magnetic force microscopy of Sr-ferrite magnet by stimulating magnetization under an AC magnetic field: Direct observation of reversible and irreversible magnetization processes

Yongze Cao, Pawan Kumar, Yue Zhao, Satoru Yoshimura, and Hitoshi Saito

Applied Physics Letters ( Applied Physics Letters )  112 ( 22 ) 223103   2018.05  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Magnetic domain structure imaging near sample surface with alternating magnetic force microscopy by using AC magnetic field modulated superparamagnetic tip

Yongze Cao, Shota Nakayama, Pawan Kumar, Yue Zhao, Yukinori Kinoshita, Satoru Yoshimura, Hitoshi Saito

Nanotechnology ( Nanotechnology )  29 ( 30 ) 305502   2018.05  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Basic Study of Electric Field Induced Magnetization Reversal of Multiferroic (Bi1-xBax)FeO₃ Thin Films at Room Temperature for Magnetic Recording Technology

Satoru Yoshimura, Yusuke Sugawara, Genta Egawa, and Hitoshi Saito

Journal of the Magnetic Society of Japan ( 公益社団法人 日本磁気学会 )  42 ( 2 ) 11 - 14   2018.02  [Refereed]

Research paper (journal)   Domestic Co-author

<p>  (Bi_1-xBa_x)FeO₃ multiferroic thin films with ferromagnetism and ferroelectricity were fabricated and applied to create magnetic recordings using an electric field. The (001)-oriented (Bi_1-xBa_x)FeO₃ thin films of which electric polarization direction is perpendicular to the film plane were fabricated onto a non-single-crystalline substrate with a Ta seedlayer / (111)-oriented Pt underlayer at a low substrate temperature of 500 ℃. A very high frequency plasma irradiation was applied during sputtering deposition of (Bi_1-xBa_x)FeO₃ to accelerate the crystallization at the low substrate temperature. The fabricated (Bi_0.6Ba_0.4)FeO₃ film exhibited hysteresis curves indicating ferromagnetic and ferroelectric behavior. The saturation magnetization of the film was approximately 60 emu/cm³ and the coercivity was approximately 2.5 kOe, respectively. Magnetic Force Microscopy analysis of the (Bi_0.6Ba_0.4)FeO₃ film confirmed that the magnetization was reversed by applying only a local electric field. The multiferroic film described here is expected to be useful for electric field-driven magnetic devices.</p>

DOI CiNii Research

AC Magnetic Field Imaging of Perpendicular Magnetic Write Head without Image Distortion on Alternating Magnetic Force Microscopy using a Cone-Shape FePt-coated Tip

Satoru Yoshimura, Fu Zheng, Shinya Yasui, Genta Egawa, and Hitoshi Saito

Journal of the Magnetic Society of Japan ( 公益社団法人 日本磁気学会 )  42 ( 1 ) 5 - 10   2018.01  [Refereed]

Research paper (journal)   Domestic Co-author

<p>  The AC magnetic field of a perpendicular magnetic write head having three surrounding shields was successfully imaged without image distortion on our alternating magnetic force microscope (A-MFM) using a newly developed cone-shape Si tip coated with an <i>L</i>1₀-FePt film. In contrast, a conventional quadrangular pyramidal Si tip coated with the <i>L</i>1₀-FePt film showed a distortion of the AC magnetic field image for the same magnetic write head. The image distortion depended on the spatial configuration between the tip and the write head. It is concluded that a round magnetic symmetry of the cone-shape FePt-coated tip is most effective for taking a clear AC magnetic field image of the perpendicular magnetic write head having three surrounding shields without distortion.</p>

DOI CiNii Research

Magnetic resonance force microscopy using ferromagnetic resonance of a magnetic tip excited by microwave transmission via a coaxial resonator

Yukinori Kinoshita, Yan Jun Li, Satoru Yoshimura, Hitoshi Saito, and Yasuhiro Sugawara

Nanotechnology ( Nanotechnology )  28 ( 48 ) 485709   2017.11  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

High resolution magnetic field energy imaging of the magnetic recording head by A-MFM with Co-GdOx super-paramagnetic tip

Pawan Kumar, Yudai Suzuki, Yongze Cao, Satoru Yoshimura, Hitoshi Saito

Applied Physics Letters ( Applied Physics Letters )  111 ( 18 ) 183105   2017.10  [Refereed]

Research paper (journal)   Domestic Co-author

DOI

Low-energy mechanically milled τ-phase MnAl alloys with high coercivity and magnetization

Wei Lu, Junchao Niu, Taolei Wang, Kada Xia, Zhen Xiang, Yiming Song, Hong Zhang, Satoru Yoshimura, Hitoshi Saito

Journal of Alloys and Compounds   675 ( 5 ) 163 - 167   2016.12  [Refereed]

Research paper (journal)   International Co-author

Quantitatively probing the magnetic behavior of individual nanoparticles by an AC field-modulated magnetic force microscopy

Xiang Li, Wei Lu, Yiming Song, Yuxin Wang, Aiying Chen, Biao Yan, Satoru Yoshimura, Hitoshi Saito

Scientific Reports   6   22467   2016.11  [Refereed]

Research paper (journal)   Domestic Co-author

High temperature exchange bias effect in melt-spun Mn55Bi45 alloys

Yiming Song, Zhen Xiang, Taolei Wang, Junchao Niu, Kada Xia, Wei Lu, Hong Zhang, Yongze Cao, Satoru Yoshimura and Hitoshi Saito

Applied Physics Letters   109   112402-1 - 112402-5   2016.10  [Refereed]

Research paper (journal)   Domestic Co-author

Exchange Springs in L10-FePt(110)/A1-FePt Bilayer Films

Y. H. Li, D. F. Zheng, H. J. Zhao, B. Du, J. Wei, S. Yoshimura, and H. Saito

IEEE TRANSACTIONS ON MAGNETICS   51 ( 11 ) 4800503   2015.10  [Refereed]

Research paper (journal)   Domestic Co-author

Pulsed magnetic field magnetic force microscope and evaluation of magnetic properties of soft magnetic tips

Y. Zheng, S. Yoshimura, G. Egawa, F. Zheng, Y. Kinoshita and H. Saito

Journal of Physics D: Applied Physics   48   335006   2015.08  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetic force microscopy using tip magnetization modulated by ferromagnetic resonance

E. Arima, Y. Naitoh, Y. J. Li, S. Yoshimura, H. Saito, H. Nomura, R. Nakatani, and Y. Sugawara

Nanotechnology   26   125701   2015.04  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetization behaviors of Fe3O4 nanoparticles studied by frequency-modulated magnetic force microscopy

X. Li, Z. Li, D. Pan, Z. Xiang, S. Yoshimura, and H. Saito

Materials Letters   125   36 - 39   2014.12  [Refereed]

Research paper (journal)   Domestic Co-author

Dynamic nanomagnetism characterization of individual magnetic nanoparticles by frequency-modulated magnetic force microscopy

X. Li, Z. Li, D. Pan, S. Yoshimura, and H. Saito

Applied Physics Letters   104   213106   2014.07  [Refereed]

Research paper (journal)   Domestic Co-author

A new method: study on individual magnetic nanoparticles by frequency-modulated magnetic force microscopy

X. Li, Z. Li, D. Pan, S. Yoshimura, and H. Saito

IEEE Transactions on Magnetics   58 ( 8 ) 6500404   2014.01  [Refereed]

Research paper (journal)   Domestic Co-author

Quantitative analysis of the magnetic domain structure in polycrystalline LaSrMnO thin films by magnetic force microscopy

Z. Li, F. Wei, S. Yoshimura, G. Li, H. Asano, H. Saito

Physical Chemistry Chemical Physics   52 ( 2 ) 628 - 633   2013.04  [Refereed]

Research paper (journal)   Domestic Co-author

Fabrication of high-coercivity FePt-MgO tip and its application to AC magnetic field imaging of perpendicular magnetic writing head by alternating magnetic force microscopy

F. Zheng, S. Yasui, G. Egawa, Y. Kinoshita, S. Yoshimura, and H. Saito

International Conference of Materials for Resources (ICMR, Akita, Japan, 2013)     239 - 243   2013.01  [Refereed]

Research paper (journal)   Domestic Co-author

Alternating electric force microscopy: static electric field gradient imaging in an air atmosphere for Ba0.7Sr0.3TiO3 ferroelectric thin film

J. Lu, Y. Kinoshita, G. Egawa, S. Yoshimura, H. Asano, and H. Saito

Journal of Applied Physics   112   124110   2012.07  [Refereed]

Research paper (journal)   Domestic Co-author

Stroboscopic imaging of an alternating magnetic field from a perpendicular magnetic recording head by frequency-modulated magnetic force microscopy

Z. Li, K. Hatakeyama, G. Egawa, S. Yoshimura, and H. Saito

Applied Physics Letter   100   222405   2012.04  [Refereed]

Research paper (journal)   Domestic Co-author

Investigation on the microstructure and magnetic properties of FePt films prepared by sequentially sputtering

L. Zhang, Z. Li, X. Liu a, J. Bai, S. Yoshimura, H. Saito, F. Wei

Materials Letters   79   235 - 237   2012.01  [Refereed]

Research paper (journal)   Domestic Co-author

Fabrication of (001) oriented TMR film with highly ordered L10-Fe(Pd,Pt) alloy films by using a very thin Fe underlayer

S. Yoshimura, S. Omiya, G. Egawa, and H. Saito

IEEE Transactions on Magnetics   47 ( 10 ) 4417 - 4420   2011.10  [Refereed]

Research paper (journal)   Domestic Co-author

Simultaneous magnetic force microscopy imaging of perpendicular and in-plane magnetic field gradient on La0.7Sr0.3MnO3 granular film with in-plane magnetization

Z. Li, G. Egawa, S. Yoshimura, G. Li, H. Asano, and H. Saito

Journal of Applied Physics   109   07D334   2011.07  [Refereed]

Research paper (journal)   Domestic Co-author

Acceleration of ordering transformation of a new Fe2(Mn,Cr)Si Heusler-alloy film by VHF plasma irradiation process during RF sputter deposition

S. Yoshimura, H. Kobayashi, G. Egawa, H. Saito, and S. Ishida

Journal of Applied Physics   109   07B751   2011.07  [Refereed]

Research paper (journal)   Domestic Co-author

Direction detectable static magnetic field imaging by frequency-modulated magnetic force microscopy with an AC magnetic field driven soft magnetic tip

H. Saito, R. Ito, G. Egawa, Z. Li, and S. Yoshimura

Journal of Applied Physics   109   07E330   2011.07  [Refereed]

Research paper (journal)   Domestic Co-author

The role of symmetry-breaking-induced interface anisotropy in [Fe/Pt]n multilayer films

Z. Li, H. Xie, X. Liu, J. Bai, F. Wei, D. Wei, S. Yoshimura, H. Saito, and X.Liu

Journal of Applied Physics   109   07D343   2011.07  [Refereed]

Research paper (journal)   Domestic Co-author

Linearity of Giant Hall resistivity versus magnetic field in Fe/Pt/[CoFe/Pt]n/Fe/Pt multilayers

M. F. Liu, X. C. Song, H. Lv, L. R. Zhang, J. M. Bai, F. L. Wei, S. Yoshimura, and H. Saito

Journal of Physics: Conference Series   226 ( 1 ) 012003   2011.01  [Refereed]

Research paper (journal)   Domestic Co-author

Investigation of magnetic field effect on L10 FePt films during two-step tempering process

Y. B. Li, H. Lv, J. M. Bai, F. L. Wei, S. Yoshimura, and H. Saito

Journal of Physics: Conference Series   226 ( 1 ) 012017   2011.01  [Refereed]

Research paper (journal)   Domestic Co-author

MFM analysis of magnetic inhomogeneity in recorded area for perpendicular magnetic recording media by simultaneous imaging of perpendicular and in-plane magnetic field gradient

S. Yoshimura, S. Omiya, G. Egawa, H. Saito, and J. Bai

Journal of Physics: Conference Series   226 ( 1 ) 012065   2011.01  [Refereed]

Research paper (journal)   Domestic Co-author

Control of magnetic anisotropy field of (001) oriented L10-Fe(PdxPt1-x) films for MRAM application

S. Yoshimura, S. Omiya, G. Egawa, H. Saito, and J. Bai

Journal of Physics: Conference Series   226 ( 1 ) 012114   2011.01  [Refereed]

Research paper (journal)   Domestic Co-author

High resolution magnetic imaging of perpendicular magnetic recording head using frequency-modulated magnetic force microscopy with a hard magnetic tip

W. Lu, Z. Li, K. Hatakeyama, G. Egawa, S. Yoshimura, and H. Saito

Applied Physics Letter   96   143104   2010.01  [Refereed]

Research paper (journal)   Domestic Co-author

High frequency magnetic field imaging by frequency modulated magnetic force microscopy

H. Saito, W. Lu, K. Hatakeyama, G. Egawa, and S. Yoshimura

Journal of Applied Physics   107   09D309   2010.01  [Refereed]

Research paper (journal)   Domestic Co-author

Characterization of Magnetic Field Distribution in a Trailing-Edge Shielded Head by Frequency-Modulated Magnetic Force Microscopy

W. Lu, K. Hatakeyama, G. Egawa, S. Yoshimura, and H. Saito

IEEE Transactions on Magnetics   46 ( 6 ) 1479 - 1482   2010.01  [Refereed]

Research paper (journal)   Domestic Co-author

High resolution MFM imaging of in-plane magnetic field gradients using transient oscillation for perpendicular magnetic recording media

G. Egawa, S. Yoshimura, T. Miyazawa, G. Li, and H. Saito

International Conference of Materials for Resources (ICMR, Akita, Japan, 2009)     345 - 349   2009.10  [Refereed]

Research paper (journal)   Domestic Co-author

Bistable control of ferromagnetic resonance frequencies in ferromagnetic trilayered dots

Y. Nozaki, K. Tateishi, S. Taharazako, S. Yoshimura, and K. Matsuyama

Journal of Applied Physics   105   13911   2009.01  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetic force microscopy of alternating magnetic field by frequency modulation of tip oscillation

H. Saito, H. Ikeya, G. Egawa, S. Ishio, and S. Yoshimura

Journal of Applied Physics   105   07D524   2009.01  [Refereed]

Research paper (journal)   Domestic Co-author

Heat-assisted magnetization reversal using pulsed laser irradiation in patterned magnetic thin film with perpendicular anisotropy

K. Waseda, R. Doi, B. Purnama, S. Yoshimura, Y. Nozaki, and K. Matsuyama

IEEE Transactions on Magnetics   44 ( 11 ) 2483 - 2486   2008.07  [Refereed]

Research paper (journal)   Domestic Co-author

Co基ホイスラー合金を用いたGMR積層膜の作製

渡邊 義典, 宍倉 千恵子, 吉村 哲, 浅野 秀文, 松井 正顯

Journal of the Magnetics Society of Japan (日本磁気学会誌)   32 ( 3 ) 308 - 311   2008.03  [Refereed]

Research paper (journal)   Domestic Co-author

Fe2Cr1-xTixSi ホイスラー合金の構造と磁性

山地 一史, 中村 泰貴, 竹田 陽一, 吉村 哲, 浅野 秀文, 松井正顯, 石田尚治

Journal of the Magnetics Society of Japan (日本磁気学会誌)   32 ( 3 ) 325 - 328   2008.03  [Refereed]

Research paper (journal)   Domestic Co-author

Influence of interlayer magnetostatic coupling on the ferromagnetic resonance properties of lithographically patterned ferromagnetic trilayers

Y. Nozaki, K. Tateishi, S. Taharazako, S. Yoshimura, and K. Matsuyama

Applied Physics Letter   92   161903   2008.01  [Refereed]

Research paper (journal)   Domestic Co-author

非単結晶基板上における(100)高配向Co2MnGe薄膜及びそれを用いた強磁性トンネル接合の作製

高野 雅志, 吉村 哲, 竹田 陽一, 浅野 秀文, 松井 正顯

Journal of the Magnetics Society of Japan (日本磁気学会誌)   32 ( 1 ) 40893   2008.01  [Refereed]

Research paper (journal)   Domestic Co-author

Crystalline structure and magnetic property of Fe2CrSi Heusler alloy films - New ferromagnetic material for high performance MRAM -

S. Yoshimura, H. Asano, Y. Nakamura, K. Yamaji, Y. Takeda, M. Matsui, S. Ishida, Y. Nozaki, and K. Matsuyama

Journal of Applied Physics   103   07D716   2008.01  [Refereed]

Research paper (journal)   Domestic Co-author

Microwave-assisted magnetization reversal in 0.36-m-wide Permalloy wires

Y. Nozaki, S. Taharazako, K. Tateishi, M. Ohta, S. Yoshimura, and K. Matsuyama

Applied Physics Letter   91   122505   2007.12  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetic force microscopy study of microwave-assisted magnetization reversal in submicron-scale ferromagnetic particles

Y. Nozaki, M. Ohta, S. Taharazako, K. Tateishi, S. Yoshimura, and K. Matsuyama

Applied Physics Letter   91   82510   2007.12  [Refereed]

Research paper (journal)   Domestic Co-author

Effect of crystallographic orientation of Co2MnGe Heusler-alloy film on its surface roughness and ordered structure

Y. Takeda, S. Yoshimura, M. Takano, H. Asano, and M. Matsui

Journal of Applied Physics   101   09J514   2007.05  [Refereed]

Research paper (journal)   Domestic Co-author

高キュリー温度Sr2CrReO6薄膜のXPS観察

高橋 佑介, 吉村 哲, 浅野 秀文, 松井 正顯

Journal of the Magnetics Society of Japan (日本応用磁気学会誌)   31 ( 3 ) 193 - 198   2007.04  [Refereed]

Research paper (journal)   Domestic Co-author

微細加工されたLa0.7Sr0.3MnO3薄膜のアニールによる回復効果

二井 優行, 岡 武宏, 吉村 哲, 浅野 秀文, 松井 正顯

Journal of the Magnetics Society of Japan (日本応用磁気学会誌)   31 ( 4 ) 333 - 337   2007.04  [Refereed]

Research paper (journal)   Domestic Co-author

Low-temperature transformation and electronic structure of (Ni1−xCox)2MnGa

Y. Takeda, K. Kodera, S. Yoshimura, H. Asano, and M. Matsui

Journal of Magnetism and Magnetic Materials   310   1838 - 1840   2007.02  [Refereed]

Research paper (journal)   Domestic Co-author

Effect of buffer layer and seedlayer materials on control of crystallographic orientation of Co2MnGe layer onto a thermally oxidized Si wafer

S. Yoshimura, M. Takano, Y. Takeda, H. Asano, and M. Matsui

Journal of Magnetism and Magnetic Materials   310   1978 - 1980   2007.02  [Refereed]

Research paper (journal)   Domestic Co-author

Oxidation Process of Mg Films by Using High Concentration Ozone for Magnetic Tunnel Junctions

S. Yoshimura, Y. Narisawa, Y. Watanabe, M. Tsunoda, and M. Takahashi

Journal of Magnetism and Magnetic Materials   312   176 - 180   2007.01  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetization switching of CoFeSiB free-layered magnetic tunnel junctions

B. S. Chun, J. Y. Hwang, J. R. Rhee, T. Kim, S. Saito, S. Yoshimura, M. Tsunoda, M. Takahashi, and Y. K. Kim

Journal of Magnetism and Magnetic Materials   303   e223 - e225   2006.01  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetization switching of NiFeSiB free layers for magnetic tunnel junctions

B. S. Chun, S. P. Ko, B. S. Oh, J. Y. Hwang, J. R. Rhee, T. W. Kim, S. Saito, S. Yoshimura, M. Tsunoda, M. Takahashi, and Y. K. Kim

Journal of Magnetism and Magnetic Materials   304   e258 - e260   2006.01  [Refereed]

Research paper (journal)   Domestic Co-author

The switching characteristics of free layer of patterned magnetic tunnel junction device

C. C. Chen, Y. R. Wang, C. Y. Kuo, J. C. Wu, L. Horng, T. Wu, S. Yoshimura, M. Tsunoda, and M. Takahashi

Journal of Magnetism and Magnetic Materials   304   e285 - e287   2006.01  [Refereed]

Research paper (journal)   Domestic Co-author

高濃度オゾン酸化法による金属Al膜の酸化過程とそれを用いて作製した強磁性トンネル接合膜の磁気抵抗効果

吉村 哲, 成澤 洋祐, 角田 匡清, 高橋 研

Journal of the Magnetics Society of Japan (日本応用磁気学会誌)   29 ( 8 ) 820 - 825   2005.08  [Refereed]

Research paper (journal)   Domestic Co-author

トンネル接合膜のTMR特性に及ぼすAl-N絶縁層へのイオン照射の効果

角田 匡清, 渡辺 義彦, 今北 健一, 吉村 哲, 高橋 研

Journal of the Magnetics Society of Japan (日本応用磁気学会誌)   29 ( 6 ) 653 - 657   2005.06  [Refereed]

Research paper (journal)   Domestic Co-author

Surface flattening processes of metal layer and their effect on transport properties of magnetic tunnel junctions with Al-N barrier

S. Yoshimura, T. Nozawa, T. Shoyama, M. Tsunoda, and M. Takahashi

Journal of Applied Physic   97   10C920   2005.05  [Refereed]

Research paper (journal)   Domestic Co-author

Radical nitridation of Al films for the barrier formation in ferromagnetic tunnel junctions

M. Tsunoda, T. Shoyama, S. Yoshimura, and M. Takahashi

Journal of Magnetism and Magnetic Materials   286   162 - 166   2005.01  [Refereed]

Research paper (journal)   Domestic Co-author

Nitridation process of Al layer by microwave-excited plasma and large magnetoresistance in Co-Fe / Al-N / Co-Fe tunnel junctions

S. Yoshimura, T. Shoyama, T. Nozawa, M. Tsunoda, and M. Takahashi

IEEE Transactions on Magnetics   40 ( 4 ) 2290 - 2292   2004.01  [Refereed]

Research paper (journal)   Domestic Co-author

強磁性トンネル接合用Al薄膜の酸化過程とマイクロ波励起プラズマ中の酸化種との相関

吉村 哲, 角田 匡清, 尾形 聡, 高橋 研

Journal of the Magnetics Society of Japan (日本応用磁気学会誌)   27 ( 12 ) 1130 - 1134   2003.12  [Refereed]

Research paper (journal)   Domestic Co-author

Effect of Naturally Adsorbed Gas on Substrate Surface on the Growth of Very Thin WCr Seedlayer

S. Yoshimura, D. D. Djayaprawira, Y. Takakuwa, and M. Takahashi

IEEE Transactions on Magnetics   39 ( 5 ) 2270 - 2272   2003.07  [Refereed]

Research paper (journal)   Domestic Co-author

Effect of Oxidation Process on Grain Size Reduction for Longitudinal Media Using Ni-baced Amorphous Seedlayer

M. Mikami, D. D. Djayaprawira, S. Yoshimura, and M. Takahashi

IEEE Transactions on Magnetics   39 ( 5 ) 2258 - 2261   2003.07  [Refereed]

Research paper (journal)   Domestic Co-author

The Effect of Very Thin Cr-based Seedlayer Material with Different Affinity for Oxygen on Thin Film Media Microstructure and Recording Properties

S. Yoshimura, D. D. Djayaprawira, Y. Takakuwa, and M. Takahashi

Journal of Applied Physics   93 ( 10 ) 8465 - 8467   2003.04  [Refereed]

Research paper (journal)   Domestic Co-author

Improvement of Exchange Bias Field by Introduction of Oxygen During Deposition of Ru Layer in Antiferromagnetic Coupled Media

D. D. Djayaprawira, H. Domon, S. Yoshimura, and M. Takahashi

Journal of Applied Physics   93 ( 10 ) 7408 - 7410   2003.04  [Refereed]

Research paper (journal)   Domestic Co-author

Dependence of Thin-Film Media Properties on the Composition of a Very Thin Cr-Based Seedlayer: Relation between Growth Form, Melting Point, Affinity for Oxygen of a Cr-Based Seedlayer, and Media Microstructure

S. Yoshimura, D. D. Djayaprawira, M. Mikami, Y. Takakuwa, and M. Takahashi

Journal of the Magnetics Society of Japan   27 ( 4 ) 234 - 240   2003.01  [Refereed]

Research paper (journal)   Domestic Co-author

Control of thin film medis microstructure by using very thin seedlayer material with different affinity for oxygen

D. D. Djayaprawira, S. Yoshimura, and M. Takahashi

Journal of Magnetics   73 ( 3 ) 106 - 114   2002.12  [Refereed]  [Invited]

Research paper (journal)   Domestic Co-author

Dependence of thin film media microstructure and recording properties on composition of very thin Cr-based seedlayer

S. Yoshimura, D. D. Djayaprawira, M. Mikami, Y. Takakuwa, and M. Takahashi

IEEE Transactions on Magnetics   38 ( 5 ) 1958 - 1960   2002.10  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetic Grain Size Reduction by Using Oxygen Exposure Process onto Very Thin WCr Seedlayer in Longitudinal Media

S. Yoshimura, D. D. Djayaprawira, M. Mikami, M. Takahashi, K. Komiyama, A. Horii, A. Ohno, and S. Katayama

Journal of Applied Physics   91 ( 10 ) 8629 - 8631   2002.04  [Refereed]

Research paper (journal)   Domestic Co-author

Study on Increasing Coercivity in CoCrPtB Media with High Pt Content

M. Mikami, D. D. Djayaprawira, H. Domon, S. Yoshimura, M. Takahashi, and K. Komiyama

Journal of Applied Physics   91 ( 10 ) 7074 - 7076   2002.04  [Refereed]

Research paper (journal)   Domestic Co-author

Dependence of Exchange Bias Field on Composition of Stabilizing Layer and Sputtering Process in Synthetic Ferrimagnetic Coupled Media

D. D. Djayaprawira, K. Komiyama, S. Yoshimura, T. Michalke, and M. Takahashi

Journal of Magnetism and Magnetic Materials   239   396 - 398   2002.03  [Refereed]

Research paper (journal)   Domestic Co-author

Correlation between Activation Volume and Intergranular Magnetic Interaction in Longitudinal Media

M. Mikami, D. D. Djayaprawira, Tham Kim Kong, S. Yoshimura, A. Horii, and M. Takahashi

IEEE Transactions on Magnetics   37 ( 4 ) 1484 - 1486   2001.10  [Refereed]

Research paper (journal)   Domestic Co-author

Improvement of Magnetic and R/W Properties in Longitudinal Media by Using CrX/Cr Dual Underlayer

D. D. Djayaprawira, A. Horii, K. Komiyama, S. Yoshimura, M. Mikami, H. Domon, and M. Takahashi

IEEE Transactions on Magnetics   37 ( 4 ) 1497 - 1499   2001.10  [Refereed]

Research paper (journal)   Domestic Co-author

Grain Size Reduction by Utilizing a Very Thin, High-melting-point WCr Seedlayer in Longitudinal Media: Media Noise Reduction in High Hkgrain Media

Journal of the Magnetics Society of Japan   25 ( 40635 ) 627 - 630   2001.04  [Refereed]

Research paper (journal)   Domestic Co-author

Novel Sputtering Process to Reduce The Grain Size and Its Distribution In Co-based Longitudinal Thin Film Media (New Seedlayer and High Kugrain Materials)

M. Takahashi, H. Shoji, D. D. Djayaprawira, and S. Yoshimura

IEEE Transactions on Magnetics   36 ( 5 ) 2315 - 2320   2000.10  [Refereed]  [Invited]

Research paper (journal)   Domestic Co-author

Media Noise Reduction In Co-based Longitudinal Media with New Co co-precipitated NiP/Al Substrate

S. Yoshimura, D. D. Djayaprawira, Tham Kim Kong, Y. Masuda, H. Shoji, and M. Takahashi

IEEE Transactions on Magnetics   36 ( 5 ) 2363 - 2365   2000.10  [Refereed]

Research paper (journal)   Domestic Co-author

Challenge to a Physical Limit in Longitudinal High Density Recording Media

M. Takahashi, H. Shoji, S. Yoshimura, and D. D. Djayaprawira

Electrochemical Society Proceedings   99 ( 34 ) 273 - 285   2000.08  [Refereed]  [Invited]

Research paper (journal)   Domestic Co-author

Grain Size Reduction by Utilizing Very Thin CrW Seedlayer and Dry-Etching Process in CoCrTaNiPt Longitudinal Media

S. Yoshimura, D. D. Djayaprawira, Tham Kim Kong, Y. Masuda, H. Shoji, and M.Takahashi

Journal of Applied Physics   87 ( 9 ) 6860 - 6862   2000.01  [Refereed]

Research paper (journal)   Domestic Co-author

Magnetic and Structural Properties of CoCrTaNiPt Longitudinal Thin Film Media

S. Yoshimura, D. D. Djayaprawira, H. Shoji, and M. Takahashi

Journal of Applied Physics   87 ( 9 ) 6866 - 6868   2000.01  [Refereed]

Research paper (journal)   Domestic Co-author

Effect of Pt on the Intergranular Exchange Coupling in CoCrTaPt Thin Film Media Prepared under Ultra Clean Sputtering Process

M. Takahashi, H. Hara, A. Kikuchi, S. Yoshimura, and H. Shoji

Journal of the Magnetics Society of Japan   23   335 - 337   1999.01  [Refereed]

Research paper (journal)   Domestic Co-author

Effect of Film Thickness on Magnetic Properties and Microstructure for CoCrTa Media Prepared under Ultra Clean Sputtering Process

M. Takahashi, A. Kikuchi, N. Iwata, S. Yoshimura, K. K. Tham, and H. Shoji

Journal of the Magnetics Society of Japan   23   739 - 741   1999.01  [Refereed]

Research paper (journal)   Domestic Co-author