Article
Chemistry, Physical
Fei Sun, Deyang Chen, Xingsen Gao, Jun-Ming Liu
Summary: BiFeO3, a single-phase multiferroic material, has various polymorphs and strong sensitivity to strain. Recent interest has been focused on emergent strain engineering in BiFeO3 thin films, using non-traditional methods to create new ground states and functionalities.
JOURNAL OF MATERIOMICS
(2021)
Article
Chemistry, Multidisciplinary
T. K. Lin, H. W. Chang, W. C. Chou, B. A. Chen, C. R. Wang, D. H. Wei, C. S. Tu, P. Y. Chen
Summary: In this study, the crystalline structure, ferroelectricity, leakage current density, magnetic, and nanomechanical properties of BiFeO3 (BFO) films with Ce substitution were investigated. The results showed that Ce substitution improved the ferroelectric and magnetic properties of BCFO films, with an increase in remanent polarization and enhanced saturation magnetization. The BCFO films also exhibited strong anti-fatigue properties and enhanced nanomechanical characteristics influenced by grain size and phase composition.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Article
Materials Science, Coatings & Films
T. K. Lin, H. W. Chang, C. R. Wang, D. H. Wei, C. S. Tu, P. Y. Chen
Summary: This study investigated the phase constitutions, ferroelectric, magnetic, and nanomechanical characteristics of BiFeO3 films with Dy substitution. The results showed that the BDFO films exhibited desired ferroelectric and ferromagnetic properties, and the hardness of the films was controlled mainly by the impeded propagation of dislocation by grain boundary. The findings suggest that the radius and magnetic moment of the Dy3+ ions play a critical role in the structural evolution and enhanced properties of the BDFO films.
SURFACE & COATINGS TECHNOLOGY
(2022)
Review
Chemistry, Multidisciplinary
Bingbing Yang, Linghua Jin, Renhuai Wei, Xianwu Tang, Ling Hu, Peng Tong, Jie Yang, Wenhai Song, Jianming Dai, Xuebin Zhu, Yuping Sun, Shujun Zhang, Xiaolin Wang, Zhenxiang Cheng
Summary: This paper summarizes the development of bismuth ferrite thin films in recent years, introduces the method and challenges of chemical solution route preparation. It also proposes an all-solution chemical-solution deposition (AS-CSD) method to prepare ferroelectric films with different orientations, and studies their growth, structure, and ferroelectric properties.
Article
Chemistry, Multidisciplinary
Wan-Rong Geng, Yun-Long Tang, Yin-Lian Zhu, Yu-Jia Wang, Bo Wu, Li-Xin Yang, Yan-Peng Feng, Min-Jie Zou, Tong-Tong Shi, Yi Cao, Xiu-Liang Ma
Summary: This study demonstrates the existence of multi-field-driven magnetoelectric-optical coupling mediated by ferroelastic switching at room temperature. It provides a framework for designing potential multifunctional magnetoelectric devices.
ADVANCED MATERIALS
(2022)
Article
Energy & Fuels
Hyunwook Song, Jong Yeog Son
Summary: La-doped epitaxial BiFeO3 (LBFO) thin films with La doping concentrations ranging from 0 to 30 % were deposited on Nb-doped single-crystal SrTiO3 substrates using pulsed laser deposition. The LBFO thin films doped with 10 % La concentration exhibited the best ferroelectric properties due to a large c/a ratio of about 1.04. As the La concentration increased, the ferroelectric polarizations of the LBFO films decreased while the ferromagnetic properties improved steadily. Moreover, the LBFO thin films showed an increased energy storage efficiency with higher La concentrations, and the LBFO thin films with 30 % La doping concentration achieved a high energy storage density of about 30.7 J/cm3.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Physics, Applied
Shaoqing Song, Longfei Jia, Shuolin Wang, Dahuai Zheng, Hongde Liu, Fang Bo, Yongfa Kong, Jingjun Xu
Summary: In this study, La and Co co-doped BiFeO3 (BLFCO) thin films were successfully fabricated, which exhibited excellent multiferroic properties and high ferroelectric polarization. These findings are significant for improving the performance of BFO multifunctional devices.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Review
Nanoscience & Nanotechnology
Hui-Chuan Liu, Si-Ming Zeng, Rui Li, Yan-Ping Jiang, Qiu-Xiang Liu, Xin-Gui Tang
Summary: The study demonstrated bipolar resistive switching and ferroelectricities of Ni0.5Zn0.5Fe2O4 (NZFO) thin films using Au/NZFO/LNO/Si structure. It was found that annealing atmosphere influences the structure and properties of NZFO, with oxygen vacancy and strain stress playing a significant role. The saturation magnetization and remnant polarization values of the samples were affected by the annealing atmosphere, with improved resistive switching property observed in NZFO annealed in nitrogen atmosphere.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Manpreet Singh, Pooja Kumari, Kamal Kishore, K. C. Verma
Summary: The study on synthesized BiFe1-xMnxO3 (BFMO) samples reveals that Mn doping affects both the ferroelectric and magnetic properties of BiFeO3, enhancing its magnetoelectric coupling capabilities, making it a suitable candidate for magnetoelectric devices.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Ceramics
J. P. Liu, Z. L. Lv, Y. X. Hou, L. P. Zhang, J. P. Cao, H. W. Wang, W. B. Zhao, C. Zhang, Y. Bai, K. K. Meng, X. G. Xu, Jun Miao
Summary: Multi-element doping is an effective method to suppress leakage in BiFeO3 films. As the number of doping elements increases, the leakage current density of the BFO films decreases, and the conduction mechanism changes.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Ceramics
Preethy Augustine, Narayana Yerol, Nandakumar Kalarikkal, B. Raneesh, M. T. Rahul, Sobi K. Chacko
Summary: The study developed nanocomposites with engineered multiferroic properties by combining soft ferromagnetic MnFe2O4 and ferroelectric BiFeO3. Characterization techniques such as XRD, FESEM, and HRTEM were used to analyze the crystallographic phase, structure, and morphology of the composites. The results demonstrate the potential application of these nanocomposites in magnetoelectric coupling, electrical performance, and magnetic response.
CERAMICS INTERNATIONAL
(2021)
Article
Physics, Multidisciplinary
P. Hemme, J-c. Philippe, A. Medeiros, A. Alekhin, S. Houver, Y. Gallais, A. Sacuto, A. Forget, D. Colson, S. Mantri, B. Xu, L. Bellaiche, M. Cazayous
Summary: This study investigates the effect of strain on the ferroelectricity and dynamic magnetic response of BiFeO3. The results show that the ferroelectric soft mode is significantly enhanced under tensile strain, and low energy magnon modes are suppressed, indicating a transition from cycloidal to homogeneous magnetic state. Effective Hamiltonian calculations reveal the competition between the ferroelectric and antiferrodistortive modes in the tensile regime.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Applied
Minghai Yao, Long Cheng, Shenglan Hao, Samir Salmanov, Mojca Otonicar, Frederic Mazaleyrat, Brahim Dkhil
Summary: Multiferroic materials have been extensively studied due to their potential for multifunctional device applications. The scarcity of single-phase multiferroics and their low coupling at temperatures above room temperature pose challenges for further applications. A perovskite-perovskite composite of 3BiFeO(3)/7BaTiO(3) with combined ferroelectricity and ferromagnetism is proposed. The sintering temperature can be tailored to achieve multiferroic properties, and the ferromagnetic characteristics are superior to solid solutions. The competition between antiferromagnetic and ferromagnetic interactions in the transition metal cation sublattice is also investigated.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Ceramics
Xia-Li Liang, Jian-Qing Dai, Chang-Chang Zhang
Summary: By co-doping Zn and Mn ions, the grain size and number of defects of BFZMO thin films were decreased, resulting in reduced leakage current density and improved ferroelectric properties.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Ceramics
Yun Mei, Zongfan Duan, Zhangyuan Li, Yuanxin Zhao, Jingyi Ni, Yulong Li, Jingyu Zhang, Yingrong Chen, Xianhui Wang, Gaoyang Zhao
Summary: The study explores the influence of Co2+ doping on the properties of Bi4Ti3O12/La0.67Sr0.33MnO3 composite thin films, showing that the BITC0.05/LSMO composite thin film exhibits excellent multiferroic properties with optimal magnetoelectric performance.
CERAMICS INTERNATIONAL
(2022)
Article
Physics, Applied
T. Ichinose, H. Naganuma
Summary: The study revealed that the BiFeO3/Ru bilayer structure exhibits both piezoelectric response and ferro-like magnetism, making it a promising candidate for the basic structure of multiferroic tunnel junctions.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
H. Honjo, K. Nishioka, S. Miura, H. Naganuma, T. Watanabe, Y. Noguchi, T. V. A. Nguyen, M. Yasuhira, S. Ikeda, T. Endoh
Summary: Perpendicular magnetic tunnel junctions (MTJs) with four synthetic anti-ferromagnetically coupled Co/Pt layers were developed and showed higher tunnel magnetoresistance ratio and stability at high temperatures compared to conventional double-SyF. In contrast, conventional double-SyF exhibited magnetization direction flipping and back-hopping under external magnetic fields.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Engineering, Electrical & Electronic
K. Nishioka, S. Miura, H. Honjo, H. Naganuma, T. V. A. Nguyen, T. Watanabe, S. Ikeda, T. Endoh
Summary: The effect of magnetic coupling on the thermal stability factor Delta in magnetic tunnel junctions (MTJs) was investigated. It was found that increasing the energy constant J(cpl) of magnetic coupling can enhance Delta, but saturates when J(cpl) exceeds a critical value J(cpl_c). The magnetic static coupling constant J(stat) was much smaller than J(cpl_c), and an interlayer exchange coupling constant J(ex_c) is required to cover the difference between J(cpl_c) and J(stat). Experimental results were in good agreement with calculations, showing that Delta can be enhanced by adjusting the stiffness constant As.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Chemistry, Multidisciplinary
Hiroshi Naganuma, Masahiko Nishijima, Hayato Adachi, Mitsuharu Uemoto, Hikari Shinya, Shintaro Yasui, Hitoshi Morioka, Akihiko Hirata, Florian Godel, Marie-Blandine Martin, Bruno Dlubak, Pierre Seneor, Kenta Amemiya
Summary: A crystallographically heterogeneous interface was fabricated by growing hexagonal graphene (Gr) on a tetragonal FePd epitaxial film. The interface exhibited a short interatomic distance and an interface perpendicular magnetic anisotropy (IPMA) through chemisorption-type van der Waals force and enhanced orbital magnetic moment. This interface structure has potential applications in high-density magnetic random-access memory (MRAM).
Article
Nanoscience & Nanotechnology
T. V. A. Nguyen, Y. Saito, H. Naganuma, S. Ikeda, T. Endoh, Y. Endo
Summary: The dynamic magnetic properties of Ta-O/Co20Fe60B20 bilayer films are greatly influenced by the oxidation condition of the Ta-O layer. The oxidation of the Ta-O layer leads to a decrease in the in-plane damping constant and an increase in the effective magnetization. The out-of-plane damping constant shows a similar trend but with a much smaller magnitude compared to the in-plane damping constant.
Article
Physics, Applied
Jundong Song, Yuga Iwamoto, Takashi Iijima, Soichiro Okamura
Summary: In this study, Pb(Zr1-x Hf x )O-3 films with different Hf concentrations were fabricated using a chemical solution deposition process. The impact of Hf concentration on energy-storage performance was evaluated. The results showed that the maximum polarization and recoverable energy density decreased with increasing Hf concentration, while the energy efficiency remained relatively high. The Pb(Zr0.9Hf0.1)O-3 film achieved the highest recoverable energy density and energy efficiency, surpassing those of single-component films, attributed to the size and homogeneity of the crystal grains.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Sho Takeda, Yoshikazu Ohara, Tetsuya Uchimoto, Hirotoshi Enoki, Takashi Iijima, Eri Tokuda, Takumi Yamada, Yuzo Nagatomo
Summary: This study investigated the feasibility of fusion sensing of eddy current testing (ECT) and ultrasonic testing (UT) as effective tools to clarify the hydrogen-embrittlement mechanism of austenitic stainless steels. Fatigue testing was conducted on hydrogen-charged and uncharged AISI 304 specimens. The effects of hydrogen exposure on martensitic transformation, crack closure, and crack face morphology were examined using ECT and UT.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Physics, Applied
Mitsuharu Uemoto, Hayato Adachi, Hiroshi Naganuma, Tomoya Ono
Summary: In this study, density functional theory was used to investigate the atomic-scale configurations, electronic and magnetic properties, and adsorption mechanism of graphene on L1(0)-FePd(001). Various atomic-scale models were proposed and the energetical stability was analyzed. The study provides insights into the physical properties of the L1(0)-FePd(001) interface and facilitates the construction of low-cost computational models.
JOURNAL OF APPLIED PHYSICS
(2022)
Review
Physics, Applied
J. Robertson, H. Naganuma, H. Lu
Summary: Magnetic tunnel junctions with MgO/Fe interfaces and perpendicular spin directions are widely used in spin-transfer torque magnetic random-access memories. The future scaling of MTJs may affect materials choices, including comparing 2D h-BN materials with existing MgO tunnel barriers. The effects of different h-BN interfacial sites on Ni or Co are compared in terms of their magnetoresistance, magnetic isotropy, and the pillow effect, balanced against the favorable chemical thermodynamics of the existing MgO barriers and MgO/Fe interfaces.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Hiroshi Naganuma, Hiroaki Honjo, Chioko Kaneta, Koichi Nishioka, Shoji Ikeda, Tetsuo Endoh
Summary: The influence of sidewall damage on the thermal stability factor of quad-interface magnetic tunnel junctions is investigated through micromagnetic simulation. Sidewall damage causes a split in the energy barrier, resulting in decreased thermal stability.
Article
Materials Science, Multidisciplinary
Tomohiro Ichinose, Hiroshi Naganuma
Summary: Evaluation of the bidirectional magnetoelectric effect in a BiFeO3/NiFeCuMo bilayer demonstrates that the electronically controlled ME effect and magnetically controlled ME effect have separate origins. The magnetically controlled ME effect is attributed to the cycloidal magnetic structure of the bulk BFO, while the electronically controlled ME effect is achieved through electric-field-induced ferroelectric polarization switching. The bidirectional ME effect is a result of the combination of the cycloidal magnetic structure throughout the film and an uncompensated weak ferromagnetic interface near the BFO/NiFeCuMo interface.
PHYSICAL REVIEW MATERIALS
(2023)
Review
Physics, Applied
Hiroshi Naganuma
Summary: The feasibility of scaling X nm-generation spintronic memory using magnetic tunnel junctions (MTJs) is investigated in order to keep up with the scaling of state-of-the-art transistors. Various solutions including magnetocrystalline anisotropy, shape magnetic anisotropy, and multi-interfacial magnetic anisotropy are proposed to overcome thermal fluctuation even at the X nm-generation. This study focuses on the high magnetocrystalline anisotropy of L1(0)-ordered alloy combined with graphene as a tunneling barrier in MTJs, and investigates their scaling potential for both 10-year data retention and nanosecond writing efficiency through micromagnetic simulation. By using a junction diameter of 7 nm, the MTJs achieve 10-year data retention and high-speed writing of 2.2 ns simultaneously.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
H. Naganuma, M. Uemoto, H. Adachi, H. Shinya, I. Mochizuki, M. Kobayashi, A. Hirata, B. Dlubak, T. Ono, P. Seneor, J. Robertson, K. Amemiya
Summary: A crystallographically heterogeneous moire interface is formed between hexagonal graphene (Gr) and tetragonal L1(0)-FePd alloy via van der Waals forces. Robust interfacial perpendicular magnetic anisotropy is observed on the L1(0)-FePd side of the Gr/L1(0)-FePd heterogeneous interface. This study focuses on the Gr side of the interface.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Computer Science, Information Systems
Kang Chen, Takasuke Irie, Takashi Iijima, Susumu Miyake, Takeshi Morita
Summary: In this study, we investigated the use of a DPLUS waveguide ultrasonic transducer for thermal ablation applications. The transducer consisted of a 1-meter long and low-loss fused quartz thin waveguide operating at an optimal frequency of 2.2 MHz. Experimental results showed that the temperature rise in tissue agreed well with simulation results under different ultrasound exposure times. Lesions were observed in the tissue after exposure times of 10 s, 20 s, and 30 s, with lesion sizes smaller than 2 mm.
Article
Computer Science, Information Systems
Kang Chen, Takasuke Irie, Takashi Iijima, Takashi Kasashima, Kota Yokoyama, Susumu Miyake, Takeshi Morita
Summary: This paper investigated the use of hard-type PZTs in Double Parabolic refLectors wave-guided Ultrasonic tranSducers (DPLUS) to achieve wide-frequency (20 kHz-2 MHz) high-power output (10 MPa). The results showed that under resonant excitation, the hard-type PZT DPLUS had significantly higher peak vibration velocity and acoustic pressure compared to soft-type piezoelectric materials DPLUS, making it suitable for various applications.
