start-ver=1.4 cd-journal=joma no-vol=126 cd-vols= no-issue=1 article-no= start-page=012901 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250102 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Dynamic domain motion enhancing electro-optic performance in ferroelectric films en-subtitle= kn-subtitle= en-abstract= kn-abstract=With the rapid advancement of information technology, there is a pressing need to develop ultracompact and energy-efficient thin-film-based electro-optic (EO) devices. A high EO coefficient in ferroelectric materials is crucial. However, substrate clamping can positively or negatively influence various physical properties, including the EO response of these films, thus complicating the development of next-generation thin-film-based devices. This study demonstrates that reversible dynamic domain motion, achieved through substrate clamping, significantly enhances the EO coefficient in epitaxial ferroelectric rhombohedral Pb(Zr, Ti)O3 thin films, where the (111) and (? 111?) domains coexist with distinct optical axes. In principle, this approach can be applied to different film-substrate systems, thereby contributing to the advancement of sophisticated EO devices based on ferroelectrics. en-copyright= kn-copyright= en-aut-name=KondoShinya en-aut-sei=Kondo en-aut-mei=Shinya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=OkamotoKazuki en-aut-sei=Okamoto en-aut-mei=Kazuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SakataOsami en-aut-sei=Sakata en-aut-mei=Osami kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TeranishiTakashi en-aut-sei=Teranishi en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KishimotoAkira en-aut-sei=Kishimoto en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NagasakiTakanori en-aut-sei=Nagasaki en-aut-mei=Takanori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamadaTomoaki en-aut-sei=Yamada en-aut-mei=Tomoaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Energy Engineering, Nagoya University kn-affil= affil-num=3 en-affil=Japan Synchrotron Radiation Research Institute (JASRI) kn-affil= affil-num=4 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Energy Engineering, Nagoya University kn-affil= affil-num=7 en-affil=Department of Energy Engineering, Nagoya University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=20 article-no= start-page=1677 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20241018 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Colossal Dielectric Constant of Nanocrystalline/Amorphous Homo-Composite BaTiO3 Films Deposited via Pulsed Laser Deposition Technique en-subtitle= kn-subtitle= en-abstract= kn-abstract=We report the pulsed laser deposition (PLD) of nanocrystalline/amorphous homo-composite BaTiO3 (BTO) films exhibiting an unprecedented combination of a colossal dielectric constant (epsilon(r)) and extremely low dielectric loss (tan delta). By varying the substrate deposition temperature (T-d) over a wide range (300-800 degrees C), we identified T-d = 550 degrees C as the optimal temperature for growing BTO films with an epsilon(r) as high as similar to 3060 and a tan delta as low as 0.04 (at 20 kHz). High-resolution transmission electron microscopy revealed that the PLD-BTO films consist of BTO nanocrystals (similar to 20-30 nm size) embedded within an otherwise amorphous BTO matrix. The impressive dielectric behavior is attributed to the combination of highly crystallized small BTO nanograins, which amplify interfacial polarization, and the surrounding amorphous matrix, which effectively isolates the nanograins from charge carrier transport. Our findings could facilitate the development of next-generation integrated dielectric devices. en-copyright= kn-copyright= en-aut-name=KondoShinya en-aut-sei=Kondo en-aut-mei=Shinya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MurakamiTaichi en-aut-sei=Murakami en-aut-mei=Taichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=PichonLoick en-aut-sei=Pichon en-aut-mei=Loick kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=Leblanc-LavoieJoel en-aut-sei=Leblanc-Lavoie en-aut-mei=Joel kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TeranishiTakashi en-aut-sei=Teranishi en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KishimotoAkira en-aut-sei=Kishimoto en-aut-mei=Akira kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=El KhakaniKhakani, My Ali en-aut-sei=El Khakani en-aut-mei=Khakani, My Ali kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Institut National de la Recherche Scientifique (INRS), Centre ?nergie, Mat?riaux et T?l?communications kn-affil= affil-num=4 en-affil=Institut National de la Recherche Scientifique (INRS), Centre ?nergie, Mat?riaux et T?l?communications kn-affil= affil-num=5 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Institut National de la Recherche Scientifique (INRS), Centre ?nergie, Mat?riaux et T?l?communications kn-affil= en-keyword=BaTiO3 kn-keyword=BaTiO3 en-keyword=thin film kn-keyword=thin film en-keyword=colossal dielectric constant kn-keyword=colossal dielectric constant en-keyword=nanocrystalline/amorphous homo-composite kn-keyword=nanocrystalline/amorphous homo-composite en-keyword=pulsed laser deposition kn-keyword=pulsed laser deposition END start-ver=1.4 cd-journal=joma no-vol=363 cd-vols= no-issue= article-no= start-page=137257 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20201210 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Sophisticated rGO synthesis and pre-lithiation unlocking full-cell lithium-ion battery high-rate performances en-subtitle= kn-subtitle= en-abstract= kn-abstract=For the application to portable devices and storage of renewable energies, high-performance lithium-ion batteries are in great demand. To this end, the development of high-performance electrode materials has been actively investigated. However, even if new materials exhibit high performance in a simple evaluation, namely half-cell tests, it is often impossible to obtain satisfactory performance with an actual battery (full cell). In this study, the structure of graphene analogs is modified in various ways to change crystallinity, disorder, oxygen content, electrical conductivity, and specific surface area. These graphene analogs are evaluated as negative electrodes for lithium-ion batteries, and we found reduced graphene oxide prepared by combination of chemical reduction and thermal treatment was the optimum. In addition, a full cell is fabricated by combining it with LiCoO2 modified with BaTiO3, which is applicable to high-speed charge?discharge cathode material developed in our previous research. In general, pre-lithiation is performed for the anode when assembling full cells. In this study, we optimized a "direct pre-lithiation" method in which the electrode and lithium foil were in direct contact before assembling a full cell, and created a lithium-ion battery with an output of 293 Wh kg?1 at 8,658 W kg?1. en-copyright= kn-copyright= en-aut-name=Camp?onBeno?t Denis Louis en-aut-sei=Camp?on en-aut-mei=Beno?t Denis Louis kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YoshikawaYumi en-aut-sei=Yoshikawa en-aut-mei=Yumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TeranishiTakashi en-aut-sei=Teranishi en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NishinaYuta en-aut-sei=Nishina en-aut-mei=Yuta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Graphene kn-keyword=Graphene en-keyword=Lithium-ion battery kn-keyword=Lithium-ion battery en-keyword=Full-cell kn-keyword=Full-cell en-keyword=LiCoO2 kn-keyword=LiCoO2 en-keyword=High-rate kn-keyword=High-rate END start-ver=1.4 cd-journal=joma no-vol=109 cd-vols= no-issue= article-no= start-page=106604 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191231 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The effects of BaTiO3 nanodots density support on epitaxial LiCoO2 thin-film for high-speed rechargeability en-subtitle= kn-subtitle= en-abstract= kn-abstract=LiCoO2 (LCO) is one of the most promising cathode materials for Li ion batteries (LIBs). However, LCO shows a rate-limiting step of Li+ migration between electrode and electrolyte interfaces, requiring LIBs to be charged under low-current conditions. For next generation batteries, it will be necessary to meet the demand for a shorter charging-time. We investigated a support method for the LCO surface to improve high C-rate performance, and revealed that the Li+ intercalation/de-intercalation reaction into/from LCO was accelerated by the introduction of a BaTiO3-LCO-electrolyte interface (triple-phase interface; TPI), due to the electric field concentration near the TPI. In this report, we investigate the dependence of high C-rate performance on the density of surface BaTiO3 nanodots using epitaxial LiCoO2 thin films created via pulsed laser deposition (PLD). As the number of nanodots increased, so did discharge capacity at 50C, becoming saturated at surface coverage over 22%. However, at 100C, the discharge capacity decreased at surface coverage over 40%. These results indicate that coalescence of nanodots reduces not only the TPI length but also the electrochemically active range at quite high C-rate. Therefore, we infer that optimal surface coverage should be varied depending on the C-rate. en-copyright= kn-copyright= en-aut-name=YasuharaSou en-aut-sei=Yasuhara en-aut-mei=Sou kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YasuiShintaro en-aut-sei=Yasui en-aut-mei=Shintaro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TeranishiTakashi en-aut-sei=Teranishi en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YoshikawaYumi en-aut-sei=Yoshikawa en-aut-mei=Yumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TaniyamaTomoyasu en-aut-sei=Taniyama en-aut-mei=Tomoyasu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ItohMitsuru en-aut-sei=Itoh en-aut-mei=Mitsuru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Laboratory for Materials and Structures, Tokyo Institute of Technology kn-affil= affil-num=2 en-affil=Laboratory for Materials and Structures, Tokyo Institute of Technology kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Laboratory for Materials and Structures, Tokyo Institute of Technology kn-affil= affil-num=6 en-affil=Laboratory for Materials and Structures, Tokyo Institute of Technology kn-affil= en-keyword=High speed chargeability kn-keyword=High speed chargeability en-keyword=Nanodots kn-keyword=Nanodots en-keyword=Density kn-keyword=Density en-keyword=Dielectrics kn-keyword=Dielectrics en-keyword=LiCoO2 kn-keyword=LiCoO2 END