Choi, Eun-Mi, Jung, Soon-Gil, Lee, Nam Hoon, Kwon, Young-Seung, Kang, Won Nam, Kim, Dong Ho, ...
The remarkably high superconducting transition temperature and upper critical field of iron(Fe)-based layered superconductors, despite ferromagnetic material base, open the prospect for...
Concurrent Magnetic and Metal-Insulator Transitions in (Eu,Sm)B_6 Single Crystals (2009)
Yeo, S., Bunder, J. E., Lin, Hsiu-Hau, Jung, Myung-Hwa, Lee, Sung-Ik
The effects of magnetic doping on a EuB_6 single crystal were investigated based on magnetic and transport measurements. A modest 5% Sm substitution for Eu changes the magnetic and transport...
Wang, X. L., Dou, S. X., Ren, Zhi-An, Yi, Wei, Li, Zheng-Cai, Zhao, Zhong-Xian, ...
We measured the initial M-H curves for a sample of the newly discovered superconductor NdFeAsO0.82Fe0.18, which had a critical temperature, Tc, of 51 K, and was fabricated at the high pressure of 6...
Avalanches Injecting Flux into the Central Hole of a Superconducting MgB2 Ring (2007)
Olsen, Age Andreas Falnes, Johansen, Tom Henning, Shantsev, Daniel, Choi, Eun-Mi, Lee, Hyun-Sook, Kim, Hyun Jung, ...
Magneto-optical imaging was used to observe dendritic flux avalanches connecting the outer and inner edges of a ring-shaped superconducting MgB2 film. Such avalanches create heated channels across...
Um, Jaegon, Kim, Beom Jun, Minnhagen, Petter, Choi, M. Y., Lee, Sung-Ik
We numerically investigate dynamic critical behaviors of two-dimensional (2D) Josephson-junction arrays with positional disorder in the scheme of the resistively shunted junction dynamics....
Olsen, Age Andreas Falnes, Johansen, Tom Henning, Shantsev, Daniel, Choi, Eun-Mi, Lee, Hyun-Sook, Kim, Hyun Jung, ...
Magneto-optical imaging was used to observe flux dendrites with opposite polarities simultaneously penetrate superconducting, ring-shaped MgB$_2$ films. By applying a perpendicular magnetic field,...
Onset of dendritic flux avalanches in superconducting films (2006)
Denisov, D. V., Shantsev, D. V., Galperin, Y. M., Choi, Eun-Mi, Lee, Hyun-Sook, Lee, Sung-Ik, ...
We report a detailed comparison of experimental data and theoretical predictions for the dendritic flux instability, believed to be a generic behavior of type-II superconducting films. It is shown...
Kim, Heon-Jung, Lee, Hyun-Sook, Kang, Byeongwon, Yim, Woon-Ha, Jo, Younghun, Jung, Myung-Hwa, ...
We studied the temperature and the angular dependences of the upper critical field ($H_{c2}(T,\theta$)) of Mg$_{1-x}$Al$_x$B$_2$ single crystals ($x = 0.12$ and 0.21) and compared with the...
Instability of defensive alliances in the predator-prey model on complex networks (2005)
Kim, Beom Jun, Liu, Jianbin, Um, Jaegon, Lee, Sung-Ik
A model of six-species food web is studied in the viewpoint of spatial interaction structures. Each species has two predators and two preys, and it was previously known that the defensive alliances...
Chia, Elbert E. M., Cheong, W., Park, Tuson, Salamon, M. B., Choi, Eun-Mi, Lee, Sung-Ik
We report measurements of the in-plane magnetic penetration depth $\Delta \lambda $(T) in single crystals of ErNi$_{2}$B$_{2}$C down to $\sim$0.1 K using a tunnel-diode based, self-inductive...
Choi, Eun-Mi, Lee, Hyun-Sook, Kim, Hyun Jung, Kang, Byeongwon, Lee, Sung-Ik, Olsen, A. A. F., ...
From the magneto optics images (MOI), the dendritic magnetic avalanche is known to appear dominantly for thin films of the newly discovered MgB$_2$. To clarify the origin of this phenomenon, we...
Schneider, T., Khasanov, R., Di Castro, D., Keller, H., Kim, Mun-Seog, Jung, C. U., ...
We present and analyze field cooled magnetization data, revealing for 0
Shengelaya, A., Khasanov, R., Eshchenko, D. G., Di Castro, D., Savic, I. M., Park, M. S., ...
Muon spin rotation (mSR) measurements of the in-plane penetration depth lambda_ab have been performed in the electron-doped infinite layer high-Tc superconductor (HTS) Sr0.9La0.1CuO2. Absence of the...
Chia, Elbert E. M., Salamon, M. B., Park, Tuson, Kim, Heon-Jung, Lee, Sung-Ik, Takeya, Hiroyuki
The coexistence of weak ferromagnetism and superconductivity in ErNi$_{2}$B$% _{2}$C suggests the possibility of a spontaneous vortex phase (SVP) in which vortices appear in the absence of an...
Anomalous Paramagnetic Effects in the Mixed State of LuNi2B2C (2004)
Park, Tuson, Sun, Y., Salamon, M. B., Malinowski, A. T., Hundley, M. F., Choi, Eun Mi, ...
Anomalous paramagnetic effects in dc magnetization were observed in the mixed state of LuNi2B2C, unlike any reported previously. It appears as a kink-like feature for H > 30 kOe and becomes more...
Tu, J. J., Choi, Eun-Mi, Kim, Hyeong-Jin, Kang, W. N., Lee, Sung-Ik, ...
We studied the far-infrared reflectance of superconducting MgB2 in and out of equilibrium using pulsed synchrotron radiation. The equilibrium data can be described by a single energy gap at 2 Delta /...
Interband scattering in MgB2 (2004)
Elsen, M., Monod, P., Tu, J. J., Choi, Eun-Mi, Kim, Hyeong-Jin, ...
The scattering process responsible for connecting the bands remains one of the last open questions on the physical properties of MgB2. Through the analysis of the equilibrium and photo-induced...
Jin, B. B., Dahm, T., Iniotakis, C., Gubin, A. I., Choi, Eun-Mi, Kim, Hyun Jung, ...
Two issues related to the microwave surface impedance Z_s of MgB_2 thin film are discussed in this Letter, both being significant for potential microwave applications. At first, a correlation between...
Kim, Heon-Jung, Kang, Byeongwon, Park, Min-Seok, Kim, Kyung-Hee, Lee, Hyun Sook, Lee, Sung-Ik
We have studied the anisotropy of the London penetration depth, which was obtained from reversible magnetization measurements with the magnetic field both parallel and perpendicular to the c-axis....
Reversible magnetization of MgB2 single crystals with a two-gap nature (2004)
Kang, Byeongwon, Kim, Heon-Jung, Park, Min-Seok, Kim, Kyung-Hee, Lee, Sung-Ik
We present reversible magnetization measurements on MgB2 single crystals in magnetic fields up to 2.5 T applied parallel to the crystal's c-axis. This magnetization is analyzed in terms of the...
Critical flux pinning and enhanced upper-critical-field in magnesium diboride films (2003)
Kunchur, M. N., Wu, C., Arcos, D. H., Ivlev, B. I., Choi, Eun-Mi, Kim, Kijoon H. P., ...
We have conducted pulsed transport measurements on c-axis oriented magnesium diboride films over the entire relevant ranges of magnetic field $0 \alt H \alt H_{c2}$ (where \hcu is the upper critical...
Park, Tuson, Chia, Elbert E. M., Salamon, M. B., Bauer, E. D., Vekhter, I., Thompson, J. D., ...
A study of the dependence of the heat capacity Cp(alpha) on field angle in LuNi2B2C reveals an anomalous disorder effect. For pure samples, Cp(alpha) exhibits a fourfold variation as the field H <...
Shan, L., Gao, H., Liu, Z. Y., Park, Min-Seok, Kim, Kyung Hee, Jung, C. U., ...
Low barrier quasiparticle tunneling spectroscopy on Sr$_{0.9}$La$_{0.1}$CuO$_2$ has been studied with PtIr/Sr$_{0.9}$La$_{0.1}$CuO$_2$ point contacts at various temperatures and magnetic fields. No...
X-ray absorption and optical spectroscopy studies of (Mg$_{1-x}$Al$_x$)B$_2$ (2003)
Yang, H. D., Liu, H. L., Kuo, M. X., Ho, P. L., Chen, J. M., ...
X-ray absorption spectroscopy and optical reflectance measurements have been carried out to elucidate the evolution of the electronic structure in (Mg$_{1-x}$Al$_{x}$)B$_{2}$ for $\emph{x}$ =...
Specific Heat Study of the Magnetic Superconductor HoNi2B2C (2003)
Park, Tuson, Salamon, M. B., Choi, Eun Mi, Kim, Heon Jung, Lee, Sung-Ik
The complex magnetic transitions and superconductivity of HoNi2B2C were studied via the dependence of the heat capacity on temperature and in-plane field angle. We provide an extended, comprehensive...
Liu, Z. Y., Wen, H. H., Shan, L., Yang, H. P., Lu, X. F., Gao, H., ...
Low temperature specific heat of the electron-doped (n-type) infinite-layer cuprate $Sr_{0.9}La_{0.1}CuO_{2}$ has been measured. The quasiparticle density of states (DOS) in the mixed state is found...
Anomalous microwave conductivity coherence peak in c-axis MgB2 thin film (2003)
Jin, B. B., Dahm, T., Gubin, A. I., Choi, Eun-Mi, Kim, Hyun Jung, Lee, Sung-IK, ...
The temperature dependence of the real part of the microwave complex conductivity at 17.9 GHz obtained from surface impedance measurements of two c-axis oriented MgB2 thin films reveals a pronounced...
Flux Noise in MgB2 Thin Films (2003)
Festin, Orjan, Svedlindh, Peter, Kang, W. N., Choi, Eun-Mi, Lee, Sung-Ik
We have performed flux noise and AC-susceptibility measurements on two 400 nm thick MgB$_2$ films. Both measurement techniques give information about the vortex dynamics in the sample, and hence the...
Zhang, G. P., Chang, G. S., Callcott, T. A., Ederer, D. L., Kang, W. N., Choi, Eun-Mi, ...
Angle-resolved soft x-ray measurements made at the boron K-edge in single crystal MgB2 provide new insights into the B-2p local partial density of both unoccupied and occupied band states. The strong...
Elastic constants of borocarbides. New approach to acoustic Measurement technique (2003)
Masalitin, E. A., Fil, V. D., Zhekov, K. R., Zholobenko, A. N., Ignatova, T. V., Lee, Sung-Ik
A new version of the phase method of determining the sound velocity is proposed and implemented. It utilizes the ``Nonius'' measurement technique and can give acceptable accuracy (~1%) in samples of...
Mixed-state transport characteristics of magnesium diboride films (2003)
Kunchur M. N., Cheng Wu, Arcos D. H., Saracila G., Eun-Mi Choi, ...
We have investigated the low-temperature (T < Tc=10) mixed-state current-voltage (IV) response of magnesium diboride films beyond the point where the superconductivity is completely destroyed and the...
The pair-breaking critical current density of magnesium diboride (2002)
Kunchur, Milind N., Lee, Sung-Ik, Kang, W. N.
The pair-breaking critical current density j_{d} of magnesium diboride was determined over its entire temperature range by a pulsed dc transport measurement. At fixed low values of current density j,...
Park, Tuson, Salamon, M. B., Choi, Eun Mi, Kim, Heon Jung, Lee, Sung-Ik
Field-angle dependent heat capacity of the non-magnetic borocarbide superconductor YNi2B2C reveals a clear fourfold oscillation, the first observation of its kind. The observed angular variations...
Growth of superconducting MgB2 thin films via postannealing techniques (2002)
Kang, W. N., Choi, Eun-Mi, Kim, Hyeong-Jin, Kim, Hyun-Jung, Lee, Sung-Ik
We report the effect of annealing on the superconductivity of MgB2 thin films as functions of the postannealing temperature in the range from 700 C to 950 C and of the postannealing time in the range...
Coherence lengths and anisotropy in MgB2 superconductor (2002)
Dulcic, A., Pozek, M., Paar, D., Choi, Eun-Mi, Kim, Hyun-Jung, Kang, W. N., ...
Field and temperature microwave measurements have been carried out on MgB2 thin film grown on Al2O3 substrate. The analysis reveals the mean field coherence length xi_{MF} in the mixed state and a...
Effects of unreacted Mg impurities on the transport properties of MgB2 (2002)
Jung, C. U., Kim, Heon-Jung, Park, Min-Seok, Kim, Mun-Seog, Kim, J. Y., Du, Zhonglian, ...
We synthesized polycrystalline MgB2 from a stoichiometric mixture of Mg and the 11 B isotope under different conditions. All the samples showed bulk superconductivity with Tc = 38~39 K. The samples...
Strongly correlated s-wave pairing in the n-type infinite-layer cuprate (2002)
Seneor, P., Vasquez, R. P., Bell, L. D., Jung, C. U., ...
Quasiparticle tunneling spectra of the electron-doped (n-type) infinite-layer cuprate Sr_{0.9}La_{0.1}CuO_2 reveal characteristics that counter a number of common phenomena in the hole-doped (p-type)...
Phonon structure in I-V characteristic of MgB$_{2}$ point-contacts (2002)
Yanson, I. K., Fisun, V. V., Bobrov, N. L., Naidyuk, Yu. G., Kang, W. N., Choi, Eun-Mi, ...
The search of the phonon structure at the above-gap energies was carried out for $d^{2}V/dI^{2}(V)$ spectra of MgB$_{2}$ point contacts with a normal metal. The two-band model is assumed not only for...
Strongly correlated s-wave superconductivity in the N-type infinite-layer cuprate (2002)
Seneor, P., Vasquez, R. P., Bell, L. D., Jung, C. U., ...
Quasiparticle tunneling spectra of the electron-doped (n-type) infinite-layer cuprate Sr0.9La0.1CuO2 reveal characteristics that counter a number of common phenomena in the hole-doped (p-type)...
Fluctuation Study of the Specific Heat of MgB2 (2002)
Park, Tuson, Salamon, M. B., Jung, C. U., Park, Min-Seok, Kim, Kyunghee, Lee, Sung-Ik
The specific heat of polycrystalline Mg$^{11}$B$_{2}$ has been measured with high resolution ac calorimetry from 5 to 45 K at constant magnetic fields. The excess specific heat above T$_{c}$ is...
Complicated nature of the gap in MgB2: magnetic field-dependent optical studies (2002)
Lee, H. J., Jung, J. H., Kim, K. W., Kim, M. W., Noh, T. W., Wang, Y. J., ...
We investigated the magnetic field (H)-dependent optical conductivity spectra of MgB2 thin film in the far-infrared region. The H-dependences can be explained by the increase of normal metallic...
Microstructure and pinning properties of hexagonal-disc shaped single crystalline MgB2 (2002)
Jung, C. U., Kim, J. Y., Chowdhury, P., Kim, Kijoon H. P., Lee, Sung-Ik, Koh, D. S., ...
We synthesized hexagonal-disc-shaped MgB2 single crystals under high-pressure conditions and analyzed the microstructure and pinning properties. The lattice constants and the Laue pattern of the...
Universal scaling of the Hall resistivity in MgB2 superconductors (2002)
Kang, W. N., Kim, Hyeong-Jin, Choi, Eun-Mi, Kim, Heon Jung, Kim, Kijoon H. P., Lee, Sung-Ik
The mixed-state Hall resistivity and the longitudinal resistivity in superconducting MgB2 thin films have been investigated as a function of the magnetic field over a wide range of current densities...
Reflection of two-gap nature in penetration depth measurements of MgB$_2$ film (2002)
Kim, Mun-Seog, Skinta, John A., Lemberger, Thomas R., Kang, W. N., Kim, Hyeong-Jin, Choi, Eun-Mi, ...
The magnetic penetration depth, $\lambda^{-2}(T)$, in the basal plane of a magnesium diboride (MgB$_2$) film was measured using a two-coil mutual inductance technique at 50 kHz. This film has...
Effect of High Energy Heavy Ion Irradiation on c-axis Oriented MgB2 Films (2002)
Olsson, R. J., Kwok, W. K., Karapetrov, G., Iavarone, M., Claus, H., Peterson, C., ...
We report on the transport, magnetization, and scanning tunneling spectroscopy measurements on c-axis oriented thin films of MgB2 irradiated with high energy heavy ions of uranium and gold. We find a...
Spectroscopic evidence for anisotropic s-wave pairing symmetry in MgB2 (2002)
Seneor, P., Vasquez, R. P., Bell, L. D., Jung, C. U., ...
Scanning tunneling spectroscopy of superconducting MgB2 (T-c = 39 K) were studied on high-density pellets and c-axis oriented films. The sample surfaces were chemically etched to remove surface...
Naidyuk, Yu. G., Yanson, I. K., Tyutrina, L. V., Bobrov, N. L., Chubov, P. N., Kang, W. N., ...
We have analyzed about 100 voltage-dependent differential resistance dV/dI(V) curves of metallic point contacts between c-axis oriented MgB$_2$ thin film and Ag, which exhibit clear Andreev...
Jin, B. B., Klein, N., Kang, W. N., Kim, Hyeong-Jin, Choi, Eun-Mi, Lee, Sung-Ik
We have measured the temperature dependence of the microwave surface impedance Zs = Rs + i\Omega\mu_0 \Lamda of two c-axis oriented MgB2 films at a frequency \Omega /(2\pi) of 17.9 GHz employing a...
Williams, G. V. M., Dupree, R., Howes, A., Kramer, S., Trodahl, H. J., Jung, C. U., ...
We report the results from a thermopower and a Cu nuclear magnetic resonance (NMR) study of the infinite CuO2 layer electron doped high temperature superconducting cuprate (HTSC), Sr0.9La0.1CuO2. We...
Bobrov, N. L., Chubov, P. N., Naidyuk, Yu. G., Tyutrina, L. V., Yanson, I. K., Kang, W. N., ...
The superconducting order parameter and electron-phonon interaction (EPI) in a MgB$_{2}$ c-axis oriented thin film are investigated by point contacts (PCs). Two superconducting gaps...
A Magnetization and Microwave Study of Superconducting MgB2 (2001)
Dulcic, A., Paar, D., Pozek, M., Williams, G. V. M., Kramer, S ., Jung, C. U., ...
We report magnetic field dependent magnetization and microwave impedance measurements on a MgB2 superconductor prepared by high pressure synthesis. We find that the upper critical field is linearly...
Optical studies of charge dynamics in c-axis oriented superconducting MgB2 films (2001)
Tu, J. J., Carr, G. L., Perebeinos, V., Homes, C. C., Strongin, M., Allen, P. B., ...
Temperature dependent optical conductivities and DC resistivity of c-axis oriented superconducting (Tc = 39.6 K) MgB2 films (~ 450 nm) have been measured. The normal state ab-plane optical...
Synthesis and pinning properties of the infinite-layer superconductor Sr0.9La0.1CuO (2001)
Jung, C. U., Kim, J. Y., Kim, Mun-Seog, Park, Min-Seok, Kim, Heon-Jung, Yao, Yushu, ...
We report the high-pressure synthesis of the electron-doped infinite-layer superconductor Sr0.9La0.1CuO2 and its superconducting properties. A Rietveld analysis of X-ray powder diffraction data...
Jung, C. U., Kim, J. Y., Park, Min-Seok, Kim, Hun-Jeong, Kim, Mun-Seog, Lee, Sung-Ik
We report on the effect of substitution for Cu on Tc of electron-doped infinite-layer superconductors Sr0.9La0.1Cu1-xRxO2, R = Zn and Ni. We found that Tc was nearly constant until x = 0.03 for R =...
High current-carrying capability in c-axis-oriented superconducting MgB2 thin films (2001)
Kim, Hyeong-Jin, Kang, W. N., Choi, Eun-Mi, Kim, Mun-Seog, Kim, Kijoon H. P., Lee, Sung-Ik
In high-quality c-axis-oriented MgB2 thin films, we observed high critical current densities (Jc) of 16 MA/cm^2 at 15 K under self fields comparable to those of cuprate high-temperature...
Superconducting properties of well-shaped MgB2 single crystal (2001)
Kim, Kijoon H. P., Choi, Jae-Hyuk, Jung, C. U., Chowdhury, P., Park, Min-Seok, Kim, Heon-Jung, ...
We report measurements of the transport and the magnetic properties of high-quality, sub-millimeter-sized MgB2 single crystals with clear hexagonal-plate shapes. The low-field magnetization and the...
Far-infrared transmission studies of c-axis oriented superconducting MgB2 thin film (2001)
Jung, J. H., Kim, K. W., Lee, H. J., Kim, M. W., Noh, T. W., Kang, W. N., ...
We reported far-infrared transmission measurements on a c-axis oriented superconducting MgB$_{2}$ thin film in the frequency range of 30 $\sim$ 250 cm$^{-1}$. We found that these measurements were...
In-plane Hall effect in c-axis-oriented MgB2 thin films (2001)
Kang, W. N., Kim, Hyeong-Jin, Choi, Eun-Mi, Kim, Heon Jung, Kim, Kijoon H. P., Lee, H. S., ...
We have measured the longitudinal resistivity and the Hall resistivity in the ab-plane of highly c-axis-oriented MgB2 thin films. In the normal state, the Hall coefficient (R_H) behaves as R_H ~ T...
Pressure dependent thermoelectric power of MgB$_2$ superconductor (2001)
Choi, E. S., Kang, W., Kim, J. Y., Park, Min-Seok, Jung, C. U., Kim, Heon-Jung, ...
We have measured temperature dependence of thermoelectric power (TEP) on MgB$_2$ superconductor under hydrostatic pressure. The sign and temperature dependence of TEP shows metallic hole carriers are...
Mun, Mi-Ock, Roh, Young Sup, Kim, Kibum, Kim, Jae Hoon, Jung, C. U., Kim, J. Y., ...
We have identifies the otical phonon modes of the superconducting infinite-layer compounds Sr$_{0.9}Ln_{0.1}$CuO$_2$ ($Ln$ = La, Gd, Sm; $T_c$ = 43 K for all) from their infrared reflectivity spectra...
X-ray Photoemission Study of the Infinite-Layer Cuprate Superconductor Sr0.9La0.1CuO2 (2001)
Vasquez, R. P., Jung, C. U., Kim, J. Y., Park, Min-Seok, Kim, Heon-Jung, Lee, Sung-Ik
The electron-doped infinite-layer superconductor Sr0.9La0.1CuO2 is studied with x-ray photoemission spectroscopy (XPS). A nonaqueous chemical etchant is shown to effectively remove contaminants and...
MgB2 superconducting thin films with a transition temperature of 39 Kelvin (2001)
Kang, W. N., Kim, Hyeong-Jin, Choi, Eun-Mi, Jung, C. U., Lee, Sung-Ik
We report the growth of high-quality c-axis-oriented epitaxial MgB2 thin films by using a pulsed laser deposition technique. The thin films grown on (1`1 0 2) Al2O3 substrates show a Tc of 39 K. The...
Spectroscopic Evidence for Anisotropic S-Wave Pairing Symmetry in MgB2 (2001)
Seneor, P., Vasquez, R. P., Bell, L. D., Jung, C. U., ...
Scanning tunneling spectroscopy of superconducting MgB$_2$ ($T_c = 39$ K) were studied on high-density pellets and c-axis oriented films. The sample surfaces were chemically etched to remove surface...
X-ray Photoemission Study of MgB2 (2001)
Vasquez, R. P., Jung, C. U., Park, Min-Seok, Kim, Heon-Jung, Kim, J. Y., Lee, Sung-Ik
A c-axis oriented thin film and a high density sintered pellet of MgB2 have been studied by x-ray photoemission spectroscopy, and compared to measurements from MgO and MgF2 single crystals. The...
Epitaxial MgB2 superconducting thin films with a transition temperature of 39 Kelvin (2001)
Kang, W. N., Kim, Hyeong-Jin, Choi, Eun-Mi, Jung, C. U., Lee, Sung-Ik
We report the growth of high-quality epitaxial MgB2 thin films on (1102) Al2O3 and (001) SrTiO3 substrates by using a pulsed laser deposition technique. The thin films grown on Al2O3 substrates show...
Fluctuation Magnetoconductance in MgB2 (2001)
Kang, W. N., Kim, Kijoon H. P., Kim, Hyeong-Jin, Choi, Eun-Mi, Park, Min-Seok, Kim, Mun-Seog, ...
We report fluctuation magnetoconductance in a MgB2 superconductor prepared under a high pressure of 3 GPa. This excess magnetoconductance, $\Delta\sigma(H)$, follows the three-dimensional scaling...
Origin of the high DC transport critical current density for the MgB2 superconductor (2001)
Kim, Kijoon H. P., Kang, W. N., Kim, Mun-Seog, Jung, C. U., Kim, Hyeong-Jin, Choi, Eun-Mi, ...
If the critical current density Jc is very high for a superconductor, then estimating its value from transport measurements is not very easy. In such cases, the value of Jc, called Jcm for magnetic...
Microstructure of the highly dense MgB2 Superconductor by transmission electron microscope (2001)
Sung, Gun Yong, Kim, Sang Hyeob, Kim, JunHo, Yoo, Dong Chul, Lee, Ju Wook, Lee, Jeong Yong, ...
The microstructure of the MgB2 superconductor sintered at high temperature under a high pressure of about 3 GPa was investigated by using a high-resolution transmission electron microscope (HRTEM)....
Kim, Mun-Seog, Jung, C. U., Kim, J. Y., Choi, Jae-Hyuk, Lee, Sung-Ik
The infinite-layer compound ACuO$_{2}$ (A $=$ alkaline-earth ions) is regarded as the most suitable material for exploring the fundamental nature of the CuO$_2$ plane because it does not contain a...
Effect of sintering temperature under high pressure in the uperconductivity for MgB2 (2001)
Jung, C. U., Park, Min-Seok, Kang, W. N., Kim, Mun-Seog, Kim, Kijoon H. P., Lee, S. Y., ...
We report the effect of the sintering temperature on the superconductivity of MgB2 pellets prepared under a high pressure of 3 GPa. The superconducting properties of the non-heated MgB2 in this high...
Hole carrier in MgB_{2} characterized by Hall Measurements (2001)
Kang, W. N., Jung, C. U., Kim, Kijoon H. P., Park, Min-Seok, Lee, S. Y., Kim, Hyeong-Jin, ...
The longitudinal resistivity rho_{xx} and Hall coefficient R_H were measured for MgB2 sintered under high pressure. We found that R_H is positive like cuprate high-Tc superconductors, and decreases...
Prominent bulk pinning effect in the MgB_2 superconductor (2001)
Kim, Mun-Seog, Jung, C. U., Park, Min-Seok, Lee, S. Y., Kim, Kijoon H. P., Kang, W N., ...
We report the magnetic-field dependence of the irreversible magnetization of the recently discovered binary superconductor MgB$_{2}$. For the temperature region of $T< 0.9T_c$, the contribution of...
Jung, C. U., Park, Min-Seok, Kang, W. N., Kim, Mun-Seog, Lee, S. Y., Lee, Sung-Ik
We report the temperature- and magnetic-field-dependent resistivity of MgB2 sintered at high temperature and high pressure condition. The superconducting transition width for the resistivity...
Two-Dimensional Nature of Four-Layer Superconductors by Inequivalent Hole Distribution (2000)
Kim, Mun-Seog, Jung, C. U., Lee, Sung-Ik, Iyo, A.
The magnetization of the four-layer superconductor CuBa_{2}Ca_{3}Cu_4O_{12-\delta} with T_c\simeq117 K is presented. The high-field magnetization around T_c(H) follows the exact two-dimensional...
Synthesis and characterization of the infinite-layer superconductor Sr_{0.9}La_{0.1}CuO_{2} (2000)
Jung, C. U., Kim, J. Y., Kim, Mun-Seog, Lee, S. Y., Lee, Sung-Ik, Ha, D. H.
We report the high-pressure synthesis of the electron-doped infinite-layer superconductor Sr_{0.9}La_{0.1}CuO_{2}. A Rietveld analysis using X-ray powder diffraction data showed that, within the...
Phenomenological Theory of Superconductivity and Magnetism in Ho$_{1-x}$Dy$_x$Ni$_2$B$_2$C (1999)
Doh, Hyeonjin, Sigrist, Manfred, Cho, B. K., Lee, Sung-Ik
The coexistence of the superconductivity and magnetism in the Ho$_{1-x}$Dy$_x$Ni$_2$B$_2$C is studied by using Ginzburg-Landau theory. This alloy shows the coexistence and complex interplay of...
Yi, Hongsuk, Yu, Jaejun, Lee, Sung-Ik
From a Monte Carlo study of the ferromagnetic Kondo lattice model for doped manganites, including the antiferromagnetic superexchange interaction ($J_{AF}$), we found that the ferromagnetic ordering...
Yang, In-Sang, Klein, M. V., Cooper, S. L., Canfield, P. C., Cho, B. K., Lee, Sung-Ik
Superconductivity-induced changes in the electronic Raman scattering response were observed for the RNi$_2$B$_2$C (R = Y, Lu) system in different scattering geometries. In the superconducting state,...
Phases from Lightly-Doped Two-Legged Spin Ladders (1999)
We study two-leg spin ladder systems analytically by using a t-J model which includes the interchain spin exchange and the interchain hopping term. The spin part is mapped to a quantum sine-Gordon...
Kang, W. N., Kim, Wan-Seon, Oh, S. J., Lee, Sung-Ik, Kim, D. H., Choi, C. H., ...
The mixed-state Hall resistivity and the longitudinal resistivity in HgBa_{2}CaCu_{2}O_{6}, HgBa_{2}Ca_{2}Cu_{3}O_{8}, and Tl_{2}Ba_{2}CaCu_{2}O_{8} thin films have been investigated as functions of...
Temperature-scaling behavior of the Hall conductivity for Hg-based superconducting thin films (1999)
Kim, Wan-Seon, Kang, W. N., Oh, S. J., Kim, Mun-Seog, Bai, Yujoung, Lee, Sung-Ik, ...
The Hall conductivities of HgBa_{2}CaCu_{2}O_{6+\delta}and HgBa_{2}Ca_{2}Cu_{3}O_{8+\delta} thin films are investigated for a magnetic field parallel to the c axis. The mixed-state Hall conductivity...
Kang, W. N., Kang, B. W., Chen, Q. Y., Wu, J. Z., Bai, Y., Chu, W. K., ...
Triple sign reversal in the mixed-state Hall effect has been observed for the first time in ion-irradiated HgBa_{2}CaCu_{2}O_{6} thin films. The negative dip at the third sign reversal is more...
Current responses and voltage fluctuations in Josephson-junction systems (1998)
Choi, Mahn-Soo, Choi, M. Y., Lee, Sung-Ik
We consider arrays of Josephson junctions as well as single junctions in both the classical and quantum-mechanical regimes, and examine the generalized (frequency-dependent) resistance, which...
Choi, Mahn-Soo, Choi, M. Y., Choi, Taeseung, Lee, Sung-Ik
We investigate the quantum phase transitions in two capacitively coupled chains of ultra-small Josephson-junctions, with emphasis on the external charge effects. The particle-hole symmetry of the...
Choi, Mahn-Soo, Choi, M. Y., Lee, Sung-Ik
We consider two chains of ultrasmall Josephson junctions, coupled capacitively with each other, and investigate the transport of particle-hole pairs and the quantum phase transitions at zero...
Dissipative Dynamics of Quantum Vortices in Superconducting Arrays (1997)
Choi, Mahn-Soo, Lee, Sung-Ik, Choi, M. Y.
We consider a two-dimensional array of ultra-small superconducting grains, weakly coupled by Josephson junctions with large charging energy. We start from an effective action based on a microscopic...
The Effects of d_{x^2-y^2}-d_{xy} Mixing on Vortex Structures and Magnetization (1996)
The structure of an isolated single vortex and the vortex lattice, and the magnetization in a $d$-wave superconductor are investigated within a phenomenological Ginzburg-Landau (GL) model including...
Exact Calculation of the Vortex-Antivortex Interaction Energy in the Anisotropic 3D XY-model (1995)
We have developed an exact method to calculate the vortex-antivortex interaction energy in the anisotropic 3D-XY model. For this calculation, dual transformation which is already known for the 2D...