Kei-ichi Koga

830 total citations
23 papers, 661 citations indexed

About

Kei-ichi Koga is a scholar working on Condensed Matter Physics, Electronic, Optical and Magnetic Materials and Materials Chemistry. According to data from OpenAlex, Kei-ichi Koga has authored 23 papers receiving a total of 661 indexed citations (citations by other indexed papers that have themselves been cited), including 13 papers in Condensed Matter Physics, 8 papers in Electronic, Optical and Magnetic Materials and 8 papers in Materials Chemistry. Recurrent topics in Kei-ichi Koga's work include Physics of Superconductivity and Magnetism (11 papers), Advanced Condensed Matter Physics (8 papers) and Graphene research and applications (4 papers). Kei-ichi Koga is often cited by papers focused on Physics of Superconductivity and Magnetism (11 papers), Advanced Condensed Matter Physics (8 papers) and Graphene research and applications (4 papers). Kei-ichi Koga collaborates with scholars based in Japan, Hungary and Spain. Kei-ichi Koga's co-authors include T. Tamegai, Yasuhiro Iye, Kunio Suzuki, Fumiko Sakai, Masaki Ichihara, Yutaka Ueda, Hiroshi Yaśuoka, Kōji Kosuge, Y. Yoshinari and Masayasu Ishikawa and has published in prestigious journals such as Physical Review Letters, Physical review. B, Condensed matter and Japanese Journal of Applied Physics.

In The Last Decade

Kei-ichi Koga

23 papers receiving 636 citations

Peers

Kei-ichi Koga

CMP

EOMM

AMPO

PARAS

Nguyen Minh Hong Vietnam

J. Scott United Kingdom

Michael A. Jensen United States

Zengjia Liu China

Yoko Miura Japan

G. E. R. Schulze Germany

D. Szaller Hungary

Ádám Butykai Hungary

S. Meenakshi India

Nguyen Minh Hong Vietnam

Kei-ichi Koga

417 ×0.9

CMP

447 ×2.0

EOMM

134 ×0.9

AMPO

123 ×1.0

16 ×0.2

PARAS

Citations per year, relative to Kei-ichi Koga Kei-ichi Koga (= 1×) peers Nguyen Minh Hong

Countries citing papers authored by Kei-ichi Koga

Since Specialization

Citations

This map shows the geographic impact of Kei-ichi Koga's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by Kei-ichi Koga with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites Kei-ichi Koga more than expected).

Fields of papers citing papers by Kei-ichi Koga

Since Specialization

Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by Kei-ichi Koga. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by Kei-ichi Koga. The network helps show where Kei-ichi Koga may publish in the future.

Co-authorship network of co-authors of Kei-ichi Koga

This figure shows the co-authorship network connecting the top 25 collaborators of Kei-ichi Koga. A scholar is included among the top collaborators of Kei-ichi Koga based on the total number of citations received by their joint publications. Widths of edges represent the number of papers authors have co-authored together. Node borders signify the number of papers an author published with Kei-ichi Koga. Kei-ichi Koga is excluded from the visualization to improve readability, since they are connected to all nodes in the network.

All Works

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20 of 20 papers shown

Itoh, Yutaka, Akihiko Hayashi, Hideki Yamagata, et al.. (1996). Cu NMR and NQR Study of CuS. Journal of the Physical Society of Japan. 65(7). 1953–1956. 6 indexed citations

Nakayama, Atsuko, et al.. (1996). Electronic and Magnetic Properties of Activated Carbon Fibers. Bulletin of the Chemical Society of Japan. 69(2). 333–339. 19 indexed citations

Otzschi, Kenji, Kei-ichi Koga, & Yutaka Ueda. (1995). Relations between Oxygen Deficiency and Structures in the La-Sr-Cu-O System. Journal of Solid State Chemistry. 115(2). 490–498. 10 indexed citations

Suzuki, Masatsugu, Itsuko S. Suzuki, C. Burr, et al.. (1994). Structural and magnetic properties ofCuCl2graphite intercalation compounds. Physical review. B, Condensed matter. 50(13). 9188–9199. 15 indexed citations

Yoshinari, Y., Hiroshi Yaśuoka, Yutaka Ueda, Kei-ichi Koga, & Kōji Kosuge. (1990). NMR Studies of¹⁷O in the Normal State of YBa₂Cu₃O_6+x. Journal of the Physical Society of Japan. 59(10). 3698–3711. 100 indexed citations

Itoh, Masayuki, Isao Yamada, Kiichi Amaya, et al.. (1990). Magnetic Phase Transitions in the Two-Dimensional Random Mixture K₂Cu_xCo_1-xF₄with Competing Exchange Interactions. Journal of the Physical Society of Japan. 59(5). 1792–1800. 11 indexed citations

Tamegai, T., Kei-ichi Koga, Kunio Suzuki, et al.. (1989). Metal-Insulator Transition in the Bi₂Sr₂Ca_1-xY_xCu₂O_8+y System. Japanese Journal of Applied Physics. 28(1A). L112–L112. 162 indexed citations

Nishihara, H., Nobuhiko Nishida, T. Takabatake, et al.. (1988). Proton NMR in Degraded Powder of YBa_2Cu_3O_ : Electrical Properties of Condensed Matter. 27(9). 1652–1657. 1 indexed citations

Tamegai, T., Akiko Watanabe, Kei-ichi Koga, I. Oguro, & Yasuhiro Iye. (1988). Characterization of a Non-Superconducting Cuprate, Bi₂Sr₂YCu₂O_8.5. Japanese Journal of Applied Physics. 27(6A). L1074–L1074. 62 indexed citations

10.

Nishihara, H., Nobuyuki Sugii, Y. Hidaka, et al.. (1988). Effect of Heat Treatment on the Low-Temperature NQR Spectrum of¹³⁹La in Single Crystals and Polycrystals of the Antiferromagnetic La₂CuO₄. Journal of the Physical Society of Japan. 57(4). 1159–1162. 5 indexed citations

11.

Nishihara, H., Nobuhiko Nishida, T. Takabatake, et al.. (1988). Proton NMR in Degraded Powder of YBa₂Cu₃O_7-δ. Japanese Journal of Applied Physics. 27(9R). 1652–1652. 22 indexed citations

12.

Tamegai, T., I. Oguro, Kei-ichi Koga, Akiko Watanabe, & Yasuhiro Iye. (1987). High-Tc superconductivity in (RE)Ba2Cu3Ox-structure, transport and magnetism. Physica B+C. 148(1-3). 453–455. 7 indexed citations

13.

Nakazawa, Yasuhiro, Masayasu Ishikawa, T. Takabatake, Kei-ichi Koga, & Kiyoyuki Terakura. (1987). Characterization of Metamorphic Phases of Ba₂YCu₃O_9-δ. Japanese Journal of Applied Physics. 26(5A). L796–L796. 70 indexed citations

14.

Mahara, Fumihiko, et al.. (1985). The First Report of the Rickettsial Infections of Spotted Fever Group in Japan; Three Clinical Cases. Kansenshogaku zasshi. 59(11). 1165–1172. 102 indexed citations

15.

Suzuki, Masatsugu, et al.. (1984). Electron Spin Resonance in Second-Stage NiCl₂-Graphite Intercalation Compound. Journal of the Physical Society of Japan. 53(8). 2745–2751. 9 indexed citations

16.

Koga, Kei-ichi & Masatsugu Suzuki. (1984). Electron Spin Resonance Study on Second-Stage MnCl₂-Graphite Intercalation Compound. Journal of the Physical Society of Japan. 53(2). 786–794. 10 indexed citations

17.

Shimizu, Masafumi, Yoshitami Ajiro, Kei-ichi Koga, & Hidetarô Abe. (1980). ESR of Singlet-Ground-State Magnets at Very Low Temperatures. Journal of the Physical Society of Japan. 49(1). 170–177. 3 indexed citations

18.

Abe, Hidetarô & Kei-ichi Koga. (1975). Two Dilute-Mn Salts Studied by ESR at Very Low Temperatures. Journal of the Physical Society of Japan. 38(1). 99–106. 6 indexed citations

19.

Abe, Hidetarô & Kei-ichi Koga. (1974). ESR Measurements at Temperatures around 0.1 K. Japanese Journal of Applied Physics. 13(7). 1145–1150. 7 indexed citations

20.

Abe, Hidetarô & Kei-ichi Koga. (1963). Resonance Study of Paramagnetic Ions Coexisting within Ordered Spin System in Copper Sulfate. Journal of the Physical Society of Japan. 18(1). 153–154. 2 indexed citations

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

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