Nonlinear Microwave Switching Response Of Bscco Single Crystals (2007)
Jacobs Balam, T. Jacobs, Balam A. Willemsen, Qiang Li, G. D. Gu, N. Koshizuka
this paper was motivated by a chance observation during the study of the microwave response of high quality Bi 2 Sr 2 Ca 1 Cu 2 O8+ffi (BSCCO) single crystals. While measuring the surface impedance,...
Superconductors with nanoscale flux pinning centers (2005)
Feng, Y, Zhang, H, Nishiyama, N, Koshizuka, N, ...
Superconductors with nanoscale flux pinning centers (2005)
Feng, Y, Zhang, H, Nishiyama, N, Koshizuka, N, ...
Superconductors with nanoscale flux pinning centers (2005)
Feng, Y, Zhang, H, Nishiyama, N, Koshizuka, N, ...
Feng, Y, Shibata, S, Koshizuka, N, Murakami, M
The irreversibility line and second magnetization peak of heavily overdoped Cu-rich Bi2Sr2CaCu2O8+x (Bi2212) single crystals are studied by accurate magnetization measurements with a field H\parallel...
Re-appearance of antiferromagnetic ordering with Zn and Ni substitution in La_{2-x}Sr_xCuO_4 (2003)
Machi, T., Kato, I., Hareyama, R., Watanabe, N., Itoh, Y., Koshizuka, N., ...
The effects of nonmagnetic Zn and magnetic Ni substitution for Cu site on magnetism are studied by measurements of uniform magnetic susceptibility for lightly doped La_{2-x}Sr_xCu_{1-z}M_zO_4 (M=Zn...
Zhao, Y., Rui, X. F., Cheng, C. H., Zhang, H., Munroe, P., Zeng, H. M., ...
MgB2-diamond nanocomposite superconductors have been synthesized by addition of nano-diamond powder. Microstructural analysis shows that the nanocomposite superconductor consists of tightly-packed...
Doping Effect of Nano-Diamond on Superconductivity and Flux Pinning in MgB2 (2003)
Cheng, C. H., Zhang, H., Zhao, Y., Feng, Y., Rui, X. F., Munroe, P., ...
Doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is suppressed...
Zn-Neighbor Cu NQR in Zn-Substituted YBa2Cu3O7-d and YBa2Cu4O8 (2003)
Itoh, Y., Machi, T., Kasai, C., Adachi, S., Watanabe, N., Koshizuka, N., ...
We studied local electronic states near Zn in optimally doped YBa$_2$(Cu$_{1-x}$Zn_x)$_3$O$_{7-\delta}$ and underdoped YBa$_2$(Cu$_{1-x}$Zn_x)$_4$O$_8$ via satellite signals of plane-site Cu(2)...
Doping effect of nano-diamond on superconductivity and flux pinning in MgB2 (2003)
The doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is...
Doping effect of nano-diamond on superconductivity and flux pinning in MgB2 (2003)
The doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is...
Time evolution of superconducting properties of MgB2 exposed to water (2003)
Machi, T, Koshizuka, N, Murakami, M
The degradation of the superconducting properties, such as the diamagnetic magnetization (Mdia), the critical current density (Jc), and the irreversibility field (Hirr) for MgB2 exposed to water has...
Ti doping on the flux pinning and chemical stability against water of MgB2 bulk material (2003)
Feng, Y, Machi, T, Huang, D, Zhou, L, ...
Ti-doped MgB2 superconductors with different doping levels were prepared by solid-state reaction at ambient pressure. Jc of the samples changes with the doping level, with the best result achieved at...
Improvement of critical current density in MgB2 by Ti, Zr and Hf doping (2003)
Goto, D, Machi, T, Koshizuka, N, Murakami, M, Arai, S
Ti, Zr and Hf doped MgB2 polycrystalline samples have been prepared by using a hot pressing technique. In Ti doped MgB2, it was found that the optimum concentration of Ti for the critical current...
Rui, X, Zhang, H, Zeng, H, ...
MgB2-diamond nanocomposite superconductors have been synthesized by addition of nanodiamond powder. Microstructural analysis shows that the nanocomposite superconductor consists of tightly packed...
Doping effect of nano-diamond on superconductivity and flux pinning in MgB2 (2003)
The doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is...
Ni-substituted sites and the effect on Cu electron spin dynamics of YBa2Cu{3-x}NixO{7-\delta} (2002)
Itoh, Y., Adachi, S., Machi, T., Ohashi, Y., Koshizuka, N.
We report Cu nuclear quadrupole resonance experiment on magnetic impurity Ni-substituted YBa$_2$Cu$_{3-x}$Ni$_x$O$_{7-\delta}$. The distribution of Ni-substituted sites and its effect on the Cu...
Anisotropic resistivity and Hall effect in MgB2 single crystals (2002)
Eltsev, Yu., Nakao, K., Lee, S., Masui, T., Chikumoto, N., Tajima, S., ...
We report resistivity and the Hall effect measurements in the normal and superconducting states of MgB2 single crystal. The resistivity has been found to be anisotropic with slightly temperature...
Anisotropic Superconducting Properties of MgB2 Single Crystals (2002)
Eltsev, Yu., Lee, S., Nakao, K., Chikumoto, N., Tajima, S., Koshizuka, N., ...
In-plane electrical transport properties of MgB2 single crystals grown under high pressure of 4-6 GPa and temperature of 1400-1700oC in Mg-B-N system have been measured. For all specimens we found...
Eltsev, Yu., Lee, S., Nakao, K., Chikumoto, N., Tajima, S., Koshizuka, N., ...
We report on study of the electronic anisotropy of the newly discovered MgB2 superconductor using the in-plane resistivity measurements in magnetic field applied perpendicular and parallel to Mg and...
Fabrication and superconducting Properties of MgB2 Compiosite Wires (2002)
Feng, Y, Pradhan, A, Zhou, L, Zhang, P, Liu, X, ...
Fabrication and superconducting Properties of MgB2 Compiosite Wires (2002)
Feng, Y, Pradhan, A, Zhou, L, Zhang, P, Liu, X, ...
Enhancement of Critical Current Density in MgB2 Bulk Superconductors by Ti Doping (2002)
Feng, Y, Machi, T, Huang, D, Fudamoto, Y, ...
We studied the Ti doping effect on the superconducting properties and microstructure of sintered MgB2 bulk polycrystals. Using Ti as a sintering assistant, we have fabricated MgB2 bulk materials...
Improved Chemical Stability to Water in Ti-doped MgB2 (2002)
Machi, T, Koshizuka, N, Murakami, M
We investigated the degradation of critical current density (Jc) and irreversibility field (Hirr) of pure and Ti-doped MgB2 bulks by exposing the samples to water for a total of 10, 48, 100, and 124...
Nanoparticle structure of MgB2 with ultrathin TiB2 grain boundaries (2002)
Huang, D, Feng, Y, Machi, T, Koshizuka, N, ...
The microstructure of the Ti-doped MgB2 which shows a significantly improved critical current density, Jc [Appl. Phys. Lett. 79, 1154 (2001)], is investigated. It is found that Ti does not occupy the...
Fabrication and superconducting Properties of MgB2 Compiosite Wires (2002)
Feng, Y, Pradhan, A, Zhou, L, Zhang, P, Liu, X, ...
Zn-doping dependence of the wipeout region around Zn in YBa2(Cu1-xZnx)4O8 (2001)
Itoh, Y., Machi, T., Watanabe, N., Adachi, S., Kasai, C., Koshizuka, N.
We estimated the spread of the magnetically enhanced regions (wipeout regions) around Zn ions in high-Tc superconductors YBa2(Cu1-xZnx)4O8 (x=0, 0.005, 0.01, and 0.022) at T=4.2 K, via the planar...
Itoh, Y., Adachi, S., Machi, T., Koshizuka, N.
We report a zero-field Cu nuclear quadrupole resonance (NQR) study on the effects of nonmagnetic Sr substitution for high-Tc superconductors, Y(Ba1-xSrx)2Cu4O8 (Tc=82-80 K for x=0-0.4), using a...
Itoh, Y., Machi, T., Koshizuka, N., Masuda, T., Uchinokura, K.
We report on a zero-field 63Cu nuclear quadrupole resonance (NQR) study of nonmagnetic Mg impurity substituted Cu1-xMgxGeO3 (single crystals; the spin-Peierls transition temperature Tsp~14, 13.5, and...
Cu NQR study of host and guest spin dynamics in impurity-doped YBa2Cu4O8 (2001)
Itoh, Y., Machi, T., Watanabe, N., Koshizuka, N.
We present the planar 63Cu nuclear spin-lattice relaxation study of impurity-doped YBa2(Cu1-xMx)4O8 (M=Ni, Zn) at T=4.2-300 K with Cu nuclear quadrupole resonance (NQR) spin-echo technique. In the...
Spin Dynamics near the Superconductor-to-Insulator Transition in Impurity-Doped YBa2Cu4O8 (2001)
Itoh, Y., Machi, T., Watanabe, N., Adachi, S., Koshizuka, N.
We studied low-frequency spin dynamics near the impurity-induced superconductor-to-insulator transition for underdoped high-Tc superconductor YBa2(Cu1-xMx)4O8 (M=Ni, Zn) using the Cu nuclear...
Johnson, P. D., Valla, T., Fedorov, A., Yusof, Z., Wells, B. O., Li, Q., ...
High-resolution photoemission is used to study the electronic structure of the cuprate superconductor, Bi2212, as a function of hole doping and temperature. A kink observed in the band dispersion in...
Resonant Spin Excitation in an Overdoped High Temperature Superconductor (2001)
He, H., Sidis, Y., Bourges, P., Gu, G. D., Ivanov, A., Koshizuka, N., ...
Transport behavior and critical current densities in MgB2 wires (2001)
Pradhan, A, Feng, Y, Koshizuka, N, Zhou, L, Zhang, P, ...
We report on the transport and magnetization properties of MgB2 wires fabricated by a powder-in-tube ~PIT! technique. Temperature and magnetic-field-dependent resistivity displays a high conductivity...
Influence of Ho substitution of Y on flux pinning in melt-processed YBCO superconductors (2001)
Feng, Y, Pradhan, A, Wu, Y, Koshizuka, N, Zhao, L
The Y1−xHoxBa2Cu3Oy (x=0, 0.2, 0.4 and 0.6) bulk samples were prepared by a ‘powder melting process' method. Their microstructure, critical current density and flux pinning behavior were...
Size effect on frequency dependence of ac loss peak in textured YBCO crystals (2001)
Feng, Y, Zhou, L, Koshizuka, N
Frequency response of ac loss peak of complex susceptibility has been investigated in different ac magnetic field for YBa2Cu3O7 textured crystals with different thickness. The ac loss peak shifts...
Feng, Y., Zhou, L., Wu, Y., Machi, T., ...
Ti-doped MgB2 superconductors with different doping levels were prepared by solid-state reaction at ambient pressure. The density, diamagnetic signal, and Jc of the samples change significantly with...
Tunneling spectroscopy of non-oxide perovskite superconductor MgCNi3 (2001)
Kinoda, Go, Nishiyama, Masato, Murakami, M, Koshizuka, N, Hasegawa, Tetsuya
We report the tunneling spectroscopy of non-oxide perovskite superconductor MgCNi3 polycrystals using a low-temperature scanning tunneling microscope. The obtained tunneling spectra clearly show a...
Feng, Y, Sun, Y, Liu, F.C., Fu, B.Q., Zhou, L., ...
We present the superconducting properties and phase compositions of Mg1-xZrxB2 bulk samples fabricated by a solid-state reaction at ambient pressure. It is found that a small amount of Zr atoms may...
Resonant Spin Excitation in an Overdoped High Temperature Superconductor (2001)
Bourges, P., Gu, G. D., He, H., Ivanov, A., Keimer, B., Koshizuka, N., ...
Temperature Dependent Scattering Rates at the Fermi Surface of Optimally Doped Bi 2212 (2000)
Valla, T., Fedorov, A. V., Johnson, P. D., Li, Q., Gu, G. D., Koshizuka, N.
For optimally doped Bi 2212, scattering rates in the normal state are found to have a linear temperature dependence over most of the Fermi surface. In the immediate vicinity of the (1,0) point, the...
Resonant Spin Excitation in an Overdoped High Temperature Superconductor (2000)
He, H., Sidis, Y., Bourges, P., Gu, G. D., Ivanov, A., Koshizuka, N., ...
An inelastic neutron scattering study of overdoped Bi_2Sr_2CaCu_2O_{8+\delta} $ (T_c = 83 K) has revealed a resonant spin excitation in the superconducting state. The mode energy is E_res=38 meV,...
Spin Excitations in Cuprates: From Underdoped to Overdoped State (2000)
Keimer, B., Bourges, P., Fong, H. F., Gu, G. D., He, H., Ivanov, A., ...
Neutron Scattering from Magnetic Excitations in Bi_2 Sr_2 Ca_2 O_8+delta (1999)
Fong, H. F., Bourges, P., Sidis, Y., Regnault, L. P., Ivanov, A., Gu, G. D., ...
Many physical properties of the copper oxide high temperature superconductors appear to defy the conventional (one-electron) theory of metals, and the development of new theories incorporating strong...
White, P. J., Shen, Z. X., Feng, D. L., Kim, C., Hasan, M. Z., Harris, J. M., ...
An angle resolved photoelectron spectroscopy study was conducted on BiSrCaCuZnO. A small amount of Zn substitution for Cu almost completely suppresses the otherwise sharp spectral peak along the...
Zn Impurities in BiSrCa(CuZn)O II - Temperature Induced Spectral Change (1999)
White, P. J., Shen, Z. X., Feng, D. L., Kim, C., Hasan, M. Z., Loeser, A. G., ...
The contents of this paper were absorbed into cond-mat/9901349.
Neutron scattering from magnetic excitations in Bi2Sr2CaCu2O8+δ. (1999)
Fong, H. F., Bourges, P., Sidis, Y., Regnault, L. P., Ivanov, A., Gu, G. D., ...
Resonant spin excitations in YBa2Cu3O6-x and Bi2Sr2CaCu2O8+δ. (1999)
Keimer, B., Bourges, P., Fong, H. F., Sidis, Y., Regnault, L. P., Ivanov, A., ...
XPS studies of high-Tc Superconducting Bi2Sr2Ca(Cu1-yFey) (2)O-x single crystals (1999)
Yang, C.F., ...
Fe-substituted Bi2Sr2Ca(Cu1-[gamma]Fe[gamma])2Ox single crystals have been studied by X-ray photoelectron spectroscopy (XPS) to determine the changes of oxidation states of their constitutes as well...
Saini, N. L., Bianconi, A., Lanzara, A., Avila, J., Asensio, M. C., Tajima, S., ...
Here we report an asymmetric suppresion of spectral weight at the Fermi surface around the M points using angle resolved photoemission spectroscopy. The results provide direct evidence for diagonal...
High energy spin excitations of a high-Tc superconductor YBa2Cu3O6.6 (1998)
Nishijima, T, Arai, M, Endoh, Y, Bennington, S M, Tajima, S, Tomimoto, K, ...
Vortex-glass liquid transition in Bi2Sr2CaCu2O8/Bi2Sr2Ca2Cu3O10 intergrowth single crystals (1998)
...
The vortex-glass-liquid transition in Bi---Sr---Ca---Cu---O (BSCCO) intergrowth single crystals in which some CuO2 trilayers are inserted into the Bi2Sr2CaCu2O8 matrix has been studied. The curvature...
Resistance Anomaly in Superconducting Fluctuation Region in Bi2Sr2CaCu2O8 Single Crystals (1997)
A resistivity anomaly near the superconducting transition temperature is observed in the ab-plane of as-grown Bi2Sr2CaCu2O8 (Bi-2 2 1 2) single crystals. The resistivity at the peak is much larger...
In-Plane Paraconductivity of Bi2Sr2CaCu2O8 Single Crystals (1997)
Superconducting fluctuations have been studied by systematic measurements of the in-plane paraconductivity in Bi2Sr2CaCu2O8 single crystals with different resistivity anisotropies. It has been...
A resistivity anomaly near the superconducting transition temperature is observed in the ab-plane of as-grown Bi2Sr2CaCu2O8 (Bi-2 2 1 2) single crystals. The resistivity at the peak is much larger...
Superconducting fluctuations have been studied by systematic measurements of the in-plane paraconductivity in Bi2Sr2CaCu2O8 single crystals with different resistivity anisotropies. It has been...
Vortex Lattice Melting and Dimensionality Crossover in Bi2Sr2CaCu2O8+x (1997)
Differential resistivity, I-V characteristics, and voltage noise have been measured to study the vortex dynamics in Bi2Sr2CaCu2O8+x single crystals. The sample shows a crossover from three to two...
Study of Bi-2212/2223 Single Crystals in Vacuum (1997)
High-quality Bi-2212 single crystals with a transition temperature of 91 K were annealed in vacuum at 550 oC for 10, 20, 40 and 72 h. AC susceptibility measurements showed that Tc and Tc increased...
Voltage noise of the Bi2Sr2CaCu2O3+x single crystal below Tc is by an asymptotic power spectrum method. The low-frequency noise, power, Sa(T), shows a peak at Y = Tp. This peak is found to be closely...
Wen, J.G., Koshizuka, N., Traeholt, C., Zandbergen, H.W., Rogalla, H.
Ramp-edge YBa2Cu3/PrBa2Cu3Ox/YBa2Cu3Ox Josephson junctions with PrBa2Cu3Ox (PrBCO) or SrTiO3 as a separating layer on different kinds of substrate have been studied by high-resolution electron...
Wen, J.G., Koshizuka, N., Traeholt, C., Zandbergen, H.W., Rogalla, H.
Ramp-edge YBa2Cu3/PrBa2Cu3Ox/YBa2Cu3Ox Josephson junctions with PrBa2Cu3Ox (PrBCO) or SrTiO3 as a separating layer on different kinds of substrate have been studied by high-resolution electron...
Wen, J.G., Koshizuka, N., Traeholt, C., Zandbergen, H.W., Rogalla, H.
Ramp-edge YBa2Cu3/PrBa2Cu3Ox/YBa2Cu3Ox Josephson junctions with PrBa2Cu3Ox (PrBCO) or SrTiO3 as a separating layer on different kinds of substrate have been studied by high-resolution electron...
The effect of annealing on the superconductivity and structure of Bi-2212 single crystals (1995)
Two types of Bi-2212 single crystals, one type having a low T c and the other having a high T¢ were annealed in air at different temperatures over the range 450°C to 750°C followed by...
The effect of annealing on the superconductivity and structure of Bi-2212 single crystals (1995)
Two types of Bi-2212 single crystals, one type having a low T c and the other having a high T¢ were annealed in air at different temperatures over the range 450°C to 750°C followed by...
Normal state reentrant phenomenon in Bi 2223/ 2212 intergrowth single crystals (1995)
Nakamura, N, Tajima, S, Koshizuka, N
Normal-state reentrant behavior is observed in the resistive transition for Bi-2212/2223 intergrowth single crystals. It is found that for a small driving current of 50 μA the resistivity for...
Fluctuation of vortices and fluxon transition in Bi2Sr2CaCu2O8+y single crystals (1995)
Cochrane, J, Wen, J, Nakamura, N, ...
An anomalously broad foot structure is observed in the zero-field resistive transition for the ab plane of Bi2Sr2CaCu2O8+y single crystals, which are found to have a high density of dislocations....
Fluctuations of vortices and fluxon transition in Bi2Sr2CaCu2O8+y Single Crystal (1995)
Wen, J, Nakamura, N, ...
An anomalously broad foot structure is observed in the zero-field resistive transition for the ab plane of Bi2Sr2CaCu2O8+y single crystals, which are found to have a high density of dislocations....
Nakamura, N, Tajima, S, Uehara, K, ...
Normal-state reentrant behavior is observed in the resistive transition for Bi-2212/2223 intergrowth single crystals. It is found that for a small driving current of 50 μA the resistivity for...
The voltage noise of a Bi2Sr2CaCu2O8+x single crystal below Tcis analyzed with an asymptotic power spectrum method. Low-frequency noise power Sv(T) shows a peak at T = Tp. Above Tp, the power...
The effect of annealing on the superconductivity and structure of Bi-2212 single crystals (1995)
Two types of Bi-2212 single crystals, one type having a low T c and the other having a high T¢ were annealed in air at different temperatures over the range 450°C to 750°C followed by...
MAGNETIC AND MAGNETO-OPTICAL PROPERTIES OF Co/Ag COMPOSITIONALLY MODULATED MULTILAYER FILMS (1988)
Katayama, T., Sugimoto, T., Suzuki, Y., Kitaguchi, T., Nishihara, Y., Koshizuka, N.
Magnetic properties and magneto-optical Kerr rotation θK spectra are studied for Co/Ag compositionally modulated multilayer films. It is shown that a new peak appears around λ = 310 nm with...
RAMAN STUDY OF La2-xBaxCuO4 (x= 0, 0.016) SINGLE CRYSTALS (1988)
Koshizuka, N., Unoki, H., Oka, K., Hayashi, K., Okuda, T., Kimura, Y.
Raman scattering of La2-xBaxCuO4 (x = 0, 0.016) single crystals has been measured at various temperatures in the frequency range between 100 and 5000 cm-1. Besides an A1g phonon line at 430 cm-1, the...
MAGNETIC AND MAGNETO-OPTICAL PROPERTIES OF Co/Ag COMPOSITIONALLY MODULATED MULTILAYER FILMS (1988)
Katayama, T., Sugimoto, T., Suzuki, Y., Kitaguchi, T., Nishihara, Y., Koshizuka, N.
Magnetic properties and magneto-optical Kerr rotation θK spectra are studied for Co/Ag compositionally modulated multilayer films. It is shown that a new peak appears around λ = 310 nm with...
RAMAN STUDY OF La2-xBaxCuO4 (x= 0, 0.016) SINGLE CRYSTALS (1988)
Koshizuka, N., Unoki, H., Oka, K., Hayashi, K., Okuda, T., Kimura, Y.
Raman scattering of La2-xBaxCuO4 (x = 0, 0.016) single crystals has been measured at various temperatures in the frequency range between 100 and 5000 cm-1. Besides an A1g phonon line at 430 cm-1, the...
MAGNETIC AND MAGNETO-OPTICAL PROPERTIES OF Co/Ag COMPOSITIONALLY MODULATED MULTILAYER FILMS (1988)
Katayama, T., Sugimoto, T., Suzuki, Y., Kitaguchi, T., Nishihara, Y., Koshizuka, N.
Magnetic properties and magneto-optical Kerr rotation θK spectra are studied for Co/Ag compositionally modulated multilayer films. It is shown that a new peak appears around λ = 310 nm with...
RAMAN STUDY OF La2-xBaxCuO4 (x= 0, 0.016) SINGLE CRYSTALS (1988)
Koshizuka, N., Unoki, H., Oka, K., Hayashi, K., Okuda, T., Kimura, Y.
Raman scattering of La2-xBaxCuO4 (x = 0, 0.016) single crystals has been measured at various temperatures in the frequency range between 100 and 5000 cm-1. Besides an A1g phonon line at 430 cm-1, the...