Kang, W. N., Kelly, F. P., Lee, N. H., Williams, R. J.
We consider a connection-level model of Internet congestion control, introduced by Massouli\'{e} and Roberts [Telecommunication Systems 15 (2000) 185--201], that represents the randomly varying...
W. N. Kang, F. P. Kelly, N. H. Lee, R. J. Williams
We consider a connection-level model of Internet congestion control, introduced by Massoulié and Roberts [33], that represents the randomly varying number of flows present in a network. Here...
Jin-tae Kim, Y. K. Park, J. -c. Park, W. N. Kang, C. W. Chu, H. R. Lim, ...
Abstract-- The effect of columnar defects on the critical dynamics of superconducting Tl2Ba2CaCu2O8 (Tl-2212) film has been investigated. The Tl-2212 film was irradiated at 0 ° C by 1.3 GeV U-ions...
T. H. Johansen, M. Baziljevich, D. V. Shantsev, Y. M. Galperin, W. N. Kang, H. J. Kim, ...
PACS. 74.60.Ge { Flux pinning, ux creep, and ux-line lattice dynamics. Abstract. { Magneto-optical imaging reveal that below 10 K the penetration of magnetic ux in MgB2 lms is dominated by dendritic...
Influence of Mg Deficiency on the Superconductivity in MgB2 Thin Films Grown by using HPCVD (2007)
Huh, Ji Young, Seong, Won Kyung, Jung, Soon-Gil, Kang, W. N.
The effects of Mg deficiency in MgB2 films grown by using hybrid physical-chemical vapor deposition were investigated after vacuum annealing at various temperatures. High-quality MgB2 films grown on...
W. N. Kang, F. P. Kelly, N. H. Lee, R. J. Williams
We consider a flow-level model of Internet congestion control introduced by Massoulié and Roberts [2]. We assume that bandwidth is shared amongst elastic documents according to a weighted...
W. N. Kang, F. P. Kelly, N. H. Lee, R. J. Williams
We consider a connection-level model of Internet congestion control, introduced
Lobo, R. P. S. M., 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)
Lobo, R. P. S. M., 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...
W. N. Kang, F. P. Kelly, N. H. Lee, R. J. Williams
We consider a connection-level model of Internet congestion control, introduced by Massoulié and Roberts [36], that represents the randomly varying number of flows present in a network. Here...
Mixed-state transport characteristics of magnesium diboride films (2003)
Kunchur,M. N., Cheng,Wu, Arcos,D. H., Saracila,G., Eun-Mi,Choi, Kim,Kijoon H.P., ...
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...
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...
Pair-breaking and superconducting state recovery dynamics in MgB2 (2003)
Demsar, J., Averitt, R. D., Taylor, A. J., Kabanov, V. V., Kang, W. N., Kim, H. J., ...
We present studies of the photoexcited quasiparticle dynamics in MgB2 where, using femtosecond optical techniques, Cooper pair breaking dynamics (PBD) have been temporally resolved for the first...
Mesoscopic flux jumps in MgB2 films visualized by magneto-optical imaging (2003)
Bobyl, A. V., Shantsev, D. V., Galperin, Y. M., Olsen, A. A. F., Johansen, T. H., Kang, W. N., ...
We report on the first spatially resolved observation of mesoscopic flux jumps in superconducting films. Magneto-optical imaging was used to visualize the flux penetration in MgB2 films subjected to...
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...
Microwave properties of MgB/sub 2/ thin films (2003)
Klein, N., Jin, B. B., Wördenweber, R., Lahl, P., Kang, W. N., Kim, H.-J., ...
This version is available at the following Publisher URL: http://ieeexplore.ieee.org/Xplore/dynhome.jsp
Anomalous coherence peak in the microwave conductivity of c-axis oriented MgB2 thin films (2003)
Jin, B. B., Dahm, T., Gubin, A. I., Choi, H. D., Kim, H.-J., Lee, S.-I., ...
This version is available at the following Publisher URL: http://prl.aps.org
Yanson, I. K., Naidyuk, Yu. G., Kvitnitskaya, O. E., Fisun, V. V., Bobrov, N. L., Chubov, P. N., ...
We review investigations of the electron-phonon interaction (EPI) in metal diborides MeB_2 (Me=Zr, Nb, Ta, Mg) by point-contact (PC) spectroscopy. For transition metal compounds the PC EPI functions...
Interplay of dendritic avalanches and gradual flux penetration in superconducting MgB2 films (2002)
Shantsev, D. V., Goa, P. E., Barkov, F. L., Johansen, T. H., Kang, W. N., Lee, S. I.
Magneto-optical imaging was used to study a zero-field-cooled MgB2 film at 9.6K where in a slowly increasing field the flux penetrates by abrupt formation of large dendritic structures....
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,...
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...
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...
Local threshold field for dendritic instability in superconducting MgB2 films (2002)
Barkov, F. L., Shantsev, D. V., Johansen, T. H., Goa, P. E., Kang, W. N., Kim, H. J., ...
Using magneto-optical imaging the phenomenon of dendritic flux penetration in superconducting films was studied. Flux dendrites were abruptly formed in a 300 nm thick film of MgB2 by applying a...
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...
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...
Current-induced dendritic magnetic instability in superconducting MgB2 films (2002)
Bobyl, A. V., Shantsev, D. V., Johansen, T. H., Kang, W. N., Kim, H. J., Choi, E. M., ...
Magneto-optical imaging reveals that in superconducting films of MgB2 a transport current creates avalanche-like flux dynamics where highly branching dendritic penetration patterns are formed. The...
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., Chen, C.-T., Yeh, N.-C., 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...
Jin, B. B., Klein, N., Kang, W. N., Kim, H.-J., Choi, H. D., Lee, S.-I., ...
This version is available at the following Publisher URL: http://prb.aps.org
Europhys. Lett., 59 (4), pp. 599--605 (2002) (2002)
Europhysics Letters August, T. H. Johansen, M. Baziljevich, D. V. Shantsev, P. E. Goa, Y. M. Galperin, ...
Magneto-optical imaging reveal that below 10 K the penetration of magnetic flux in MgB2 films is dominated by dendritic structures abruptly formed in response to an applied field. The dendrites show...
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...
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...
Magnetic relaxation and critical current density of $MgB_2$ thin films (2001)
Wen, H. H., Li, S. L., Zhao, Z. W., Jin, H., Ni, Y. M., Kang, W. N., ...
Magnetic relaxation and critical current density have been measured on a $MgB_2$ thin film in a wide region of temperature with the magnetic field up to 8 T. The irreversibility line has also been...
Dendritic flux patterns in MgB2 films (2001)
Johansen, T. H., Baziljevich, M., Shantsev, D. V., Goa, P. E., Galperin, Y. M., Kang, W. N., ...
Magneto-opitcal studies of a c-oriented epitaxial MgB2 film with critical current density 10^7 A/cm^2 demonstrate a breakdown of the critical state at temperatures below 10 K [cond-mat/0104113]....
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...
Anisotropic Superconductivity in Epitaxial MgB2 Films (2001)
Jung, M. H., Jaime, M., Lacerda, A. H., Boebinger, G. S., Kang, W. N., Kim, H. J., ...
High-quality epitaxial MgB2 thin films prepared by pulsed laser deposition with Tc = 39 K offer the opportunity to study the anisotropy and robustness of the superconducting state in magnetic fields....
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...
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., Chen, C. -T., Yeh, N. -C., 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...
Zhao, Z. W., Li, S. L., Ni, Y. M., Yang, H. P., Liu, Z. Y., Wen, H. H., ...
By doing magnetization measurements during magnetic field sweeps on thin films of the new superconductor $MgB_2$, it is found that in a low temperature and low field region small flux jumps are...
Dendritic magnetic instability in superconducting MgB2 films (2001)
Johansen, T. H., Baziljevich, M., Shantsev, D. V., Goa, P. E., Galperin, Y. M., Kang, W. N., ...
Magneto-opitcal studies of a c-oriented epitaxial MgB2 film show that below 10 K the global penetration of vortices is dominated by complex dendritic structures abruptly entering the film. We suggest...
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)....
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...
High Current-Carrying Capability in c-Axis-Oriented Superconducting MgB2 Thin Films (2001)
Choi, Eun-Mi, Kang, W. N., Kim, Hyeong-Jin, Kim, Kijoon H. P., Kim, Mun-Seog
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...