Papers - Miyamoto, Akihito

Carbon materials for negative electrode of secondary battery and manufacturing process

K Watanabe, N Nanai, K Nichogi, A Miyamoto, S Tsuchiya

US Patent 6,316,146  2001

Nonaqueous secondary battery, constituent elements of battery, and materials thereof

K Watanabe, K Nichogi, N Nanai, A Miyamoto, S Tsuchiya

US Patent App. 09/878,613  2001

Electrical and Structural Properties and Phase Diagram of a Molecular Superconductor β-[(CH<inf>3</inf>)<inf>4</inf>N][Pd(dmit)<inf>2</inf>]<inf>2</inf>

Kobayashi A., Miyamoto A., Kato R., Sato A., Kobayashi H.

Bulletin of the Chemical Society of Japan (Bulletin of the Chemical Society of Japan)  71 ( 5 ) 997 - 1006 1998.05

ISSN  00092673

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β-[(CH3)4N][Pd(dmit)2]2 is isomorphic to [(CH3)4N][Ni(dmit)2]2, which is the first pure π acceptor molecular conductor exhibiting a superconducting transition. The crystal structure at low temperature, pressure dependence of the resistivity and the magnetic susceptibility of β-[(CH3)4N][Pd(dmit)2]2 were examined. The general features of the phase diagram of β-[(CH3)4N][Pd(dmit)2]2 resemble those of the organic superconductors. At ambient pressure, the resistivity increases gradually with lowering temperature. A superconducting transition was observed at 6-9 kbar. The highest Tc was 6.5 K. Between 5 and 6.3 kbar, a characteristic rapid resistivity decrease was observed at the small temperature range above the offset temperature of the superconducting transition. Although the resistivity is not zero, this temperature region can be regarded as a "pre-superconducting region, "Above 9 kbar the metallic state is stabilized down to low temperature. Above 5 kbar, most of the crystals exhibited resistivity anomalies around 60 K, which may be ascribed to the metalinsulator transition of the domains with α-type structure (α-[(CH4)4N][Pd(dmit)2]2), which became mixed in with the crystals of β-[(CH3)4N][Pd(dmit)2]2. The resistivity data of the highly conducting state were very noisy in the pressure range where the superconducting transition could be observed.

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Electrical and Structural Properties and Phase Diagram of a Molecular Superconductor β-[(CH3)4N][Pd(dmit)2]2

A Kobayashi, A Miyamoto, R Kato, A Sato, H Kobayashi

Bulletin of the Chemical Society of Japan 71 (5), 997-1006  1998

Master Thesis, Toho University Master Thesis, Toho University, 1992

A Kobayashi, A Miyamoto, R Kato, A SATO, H KOBAYASHI

Bulletin of the Chemical Society of Japan 71 (5), 997-1006  1998

Pattern classification in a perceptron circuit using lead phthalocyanine films

KNK Nichogi, AMA Miyamoto, MMM Murakami

Japanese journal of applied physics 36 (7R), 4509 (Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers)  36 ( 7 A ) 4509 - 4512 1997.07

ISSN  00214922

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Evaporated films of lead phthalocyanine (PbPc) show a unique conductivity change after a very slight amount of gases are adsorbed. The change in the conductivity of the films depends on the polarity and the strength of input voltages, and therefore is analogous to the change of synaptic connections in nerve systems. Therefore, a perceptron circuit has been fabricated using PbPc films as synaptic connections. After learning via loading of input signals and teacher signals, this circuit can classify random inputs of eight-dimensional voltage patterns into two categories when the input patterns are linearly separable.

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Development of Organic Thin Film Devices with Synaptic Plasticity and Their Application to the Neural Devices

K Nichogi, A Miyamoto, M Murakami

FED ジャ-ナル 8 (1), 43-46  1997

高圧力の科学と技術= The Review of high pressure science and technology 7, 532-534, 1998

A Kobayashi, A Miyamoto, R Kato, A SATO, H KOBAYASHI, N Hanasaki, ...

J. Phys. Soc. Jpn 65, 538  1996

Structural analysis of Langmuir-Blodgett films of alkylated tetracyanoquinodimethanes

KNK Nichogi, TNT Nambu, AMA Miyamoto, MMM Murakami

Japanese journal of applied physics 34 (9R), 4956 (Japanese Journal of Applied Physics)  34 ( 9R ) 4956 - 4962 1995.09

ISSN  00214922

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Structural characterization of alkylated tetracyanoquinodimethane (TCNQ) Langmuir and Langmuir-Blodgett (LB) films has been carried out. Scanning electron microscope (SEM) and atomic force microscope (AFM)observations reveal numerous platelet microcrystal domains in the alkylated TCNQ Langmuir films transferredonto a quartz substrate. The analysis of height distribution in the AFM data proves that these domains haveperiodic layered structure. The thickness of these layered structures agrees well with the d-values obtained byX-ray diffraction analysis of the alkylated TCNQ LB films. Moreover, the high-resolution AFM image and thed-value of the 2-dodecyl-TCNQ Langmuir film suggest that the structure of the second and the upper layers inthe domains is identical to that of the single crystal. SEM and AFM measurements prove that the LB filmsconsist of numerous platelet microcrystal domains which are superposed upon each other, resembling a mosaicstructure. Therefore, the periodic structures observed in X-ray diffraction measurements of the alkylated TCNQLB films are ascribed to the layered structure in these domains, although they are usually explained as well-definedmultilayered structure. © 1995 The Japan Society of Applied Physics.

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Structural control of evaporated lead-phthalocyanine films

A Miyamoto, K Nichogi, A Taomoto, T Nambu, M Murakami

Thin Solid Films 256 (1-2), 64-67 (Thin Solid Films)  256 ( 1-2 ) 64 - 67 1995.02

ISSN  00406090

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Monoclinic lead-phthalocyanine crystal film having only (320) orientation and monoclinic crystal film composed of lower (200)-and upper (320)-rich orientation were obtained at a substrate temperature of 293 K, and deposition rates higher than 1.0 nm s-1 and from 0.8 to 0.2 nm s-1, respectively. A film consisting of mixed triclinic and monoclinic crystals in which the distribution was almost homogeneous was obtained at a substrate temperature of 293 K and a deposition rate of 0.1 nm s-1, and a pure triclinic crystal film was obtained at a substrate temperature of 373 K. © 1995.

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New molecular superconductors, ß-[(CH<inf>3</inf>)<inf>4</inf>N][PD(dmit)<inf>2</inf>]<inf>2</inf> and [(CH<inf>3</inf>)<inf>2</inf>(C<inf>2</inf>H<inf>5</inf>)<inf>2</inf>N][Pd(dmit)<inf>2</inf>]<inf>2</inf>

Kobayashi A., Kato R., Clark R.A., Underhill A.E., Miyamoto A., Bun K., Naito T., Kobayashi H.

Synthetic Metals (Synthetic Metals)  56 ( 2-3 ) 2927 - 2932 1993.04

ISSN  03796779

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High-pressure resistivity studies on ß-[CH3)4N][Pd(dmit)2]2 and [(CH3C2H5)2N]-[Pd(dmit)2]2 have revealed the system to be new molecular superconductors with Tc=6.3 K at 6.5 kbar and Tc=4K at 2.4kbar, respectively. ß-[(CH3)4][Pd(dmit)2]2, though they have the isomorphous to the high-pressure superconductor, [(CH3)4N][Ni(dmit)2]2 has the structure almost dimeric columns of Pd(dmit)2 molecules. The determination of the phase diagram has revealed the existence of a narrow temperature region where the superconducting phase invades into the insulating phase. The crystal of [(CH3)2(C2H5)2N][Pd(dmit)2]2 belongs to triclinic system and has the dimeric columns of Pd(dmit)2. It is of interest that the insulating phase emerges when superconducting state is suppressed at high pressure. © 1993.

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Electrical and structural properties of κ-type organic conductor

T Naito, K Bun, A Miyamoto, H Kobayashi, H Sawa, R Kato, A Kobayashi

Synthetic metals 56 (1), 2234-2240 (Synthetic Metals)  56 ( 1 ) 2234 - 2240 1993.03

ISSN  03796779

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The electrical resistivities of organic metals with κ-type molecular arrangements were examined. Superconducting transition temperature (Tc) of alloy system κ-[(ET)1-x(STF)x]2 Cu[N(CN)2]Br (ET=BEDT-TTF, STF=BEDT-DSeDTF) is rapidly depressed with increase of the doping amount of the asymmetric π-donor STF. Tc becomes lower than 1.6 K at x>0.25 but the system retains metallic state at least up to x=0.6. The characteristic resistivity maximum is smeared with increasing x. The metal-insulator transition of κ-ET2Au(CN)2 at 70 K is suppressed by applying "soft pressure" of about 550 bar. The electrical properties and the crystal stuctures of κ-MT2Cu[N (CN)2]X (MT=BMDT-TTF, XCl, Br) were also examined. The crystal of κ-MT2Cu[N(CN)2]X belongs to monoclinic system with space group Cc. The structure of anion sheet closely resembles that of κ-MT2Cu[N(CN)2]X. The electrical resistivity decreases monotonously down to 2 K. © 1993.

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Mixed valency of Cu, electron-mass enhancement, and three-dimensional arrangement of magnetic sites in the organic conductors ( , -N,N’-dicyanoquinonediimine Cu …

H Kobayashi, A Miyamoto, R Kato, F Sakai, A Kobayashi, Y Yamakita, ...

Physical Review B 47 (7), 3500  1993

Mixed valency of Cu, electron-mass enhancement, and three-dimensional arrangement of magnetic sites in the organic conductors (R1,R2-N,N'-dicyanoquinonediimine)2Cu (where R1,R2=CH3,CH3O,Cl,Br)

Kobayashi H., Miyamoto A., Kato R., Sakai F., Kobayashi A., Yamakita Y., Furukawa Y., Tasumi M., Watanabe T.

Physical Review B (Physical Review B)  47 ( 7 ) 3500 - 3510 1993

ISSN  01631829

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The unique molecular conductors with pπ-d mixing band structures (R1,R2-N,N'-dicyanoquinonediimine)2Cu [(R1,R2-DCNQI)2Cu] (R1,R2=CH3,CH3O,Cl,Br) were examined. General features of the phase diagram of the DCNQI-Cu system were depicted. A region that is related to the existence of anomalously heavy-metal electrons has been found. The T2 dependence of the low-temperature resistivity of the alloyed system (DMe1-xMeBrx-DCNQI)2Cu (where Me=CH3) suggests a large enhancement of the electron mass at the critical situation where the system begins to exhibit a characteristic metal instability. The mixed valency of Cu (Cu+1.3) in (DMe-DCNQI)2Cu was confirmed by ir experiments performed on neutral DMe-DCNQI crystals and (DMe-DCNQI)2M (M=Li, Ba, Cu). The same conclusion was also derived from a low-temperature x-ray-diffraction experiment. The gradual temperature dependences of the ir absorption intensities of totally symmetric modes of (DBr-DCNQI)2Cu observed below the metal-insulator transition temperature (TMI) are in contrast with the discontinuous resistivity and susceptibility changes at TMI. This may be attributable to the existence of two driving forces characterizing the M-I transition. One is the sharp charge ordering in Cu sites and the other is the continuous development of charge-density waves on DCNQI stacks. The arrangement of Cu2+ and Cu+ below TMI was determined by an x-ray crystal-structure analysis of the threefold insulating phase of (MeBr-DCNQI)2Cu at 110 K. The nearest-neighbor Cu2+ ions interact with each other via two DCNQI molecules. A plausible spin structure of the antiferromagnetic ground state was proposed. According to this spin-structure model, the magnetic moments of Cu2+ along the crystallographic c axis will be arranged ferromagnetically. © 1993 The American Physical Society.

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New molecular superconductors, ß-[(CH3) 4N][PD (dmit) 2] 2 and [(CH3) 2 (C2H5) 2N][Pd (dmit) 2] 2

A Kobayashi, R Kato, RA Clark, AE Underhill, A Miyamoto, K Bun, T Naito, ...

Synthetic metals 56 (2-3), 2927-2932  1993

Chem., Int. Ed. Engl. Chem., Int. Ed. Engl. 25, 740, 1986

A MIYAMOTO, H KOBAYASHI, R KATO, A KOBAYASHI, Y NISHIO, ...

Chemistry letters 1992 (1), 115-118  1992

Superconducting Transition Temperature of the Organic Alloy System. κ-[(BEDT-TTF)1−x(BEDT-STF)x]2Cu[N(CN)2]Br

T Naito, A Miyamoto, H Kobayashi, R Kato, A Kobayashi1

Chemistry letters 21 (1), 119-122  1992

Metal Instability of (DMe-DCNQI)2Cu Induced by Uniaxial Stress and Enhancement of Electron Mass

A Miyamoto, H Kobayashi, R Kato, A Kobayashi, Y Nishio, K Kajita, ...

Chemistry letters 21 (1), 115-118  1992

Superconducting Transition Temperature of the Organic Alloy System.. KAPPA.-((BEDT-TTF) 1-x (BEDT-STF) x) 2Cu (N (CN) 2) Br.

T Naito, A Miyamoto, H Kobayashi, R Kato, A Kobayashi1

Chemistry letters, 119-122  1992

Instability of metallic state of DCNQICu system

Kobayashi H., Miyamoto A., Moriyama H., Nishio Y., Kajita K., Sasaki W., Sakai F., Kato R., Kobayashi A.

Physica C: Superconductivity and its applications (Physica C: Superconductivity and its applications)  185-189 ( PART 4 ) 2695 - 2696 1991.12

ISSN  09214534

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Electrical resistivity of (MeBrDCNQI)2Cu1-xLix shows that the metal-insulator transition of (MeBrDCNQI)2Cu at 155 K is rapidly suppressed with increasing x. The mixed-cation system with x=0.2-0.5 retains a metallic state down to 4 K. The metal instability of DCNQICu is discussed in the light of the mixed-valency of Cu. © 1991.

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