• Progress in Superconductivity
• /
• v.8 no.2
• /
• pp.138-142
• /
• 2007

We observed discrete fluxon-flow resonance steps in high magnetic fields in a stack of Josephson junctions with lateral size of $1.5{\times}17{\mu}m^2$. The measurement sample was prepared by sandwiching a stack of $Bi_2Sr_2CaCu_2O_{8+x}$ intrinsic Josephson junctions between two Au electrodes by using the double-side-cleaving technique. This technique allowed us to isolate the intrinsic Josephson junction structures from the inductive interference of the basal stack. The resonance steps observed are in good agreement with the collective Josephson fluxon dynamics that are in resonance with the plasma oscillation modes inside the stacked Josephson junctions.

• 한국초전도학회:학술대회논문집
• /
• v.9
• /
• pp.178-184
• /
• 1999

We have measured I-V characteristics of Bi$_2Sr_2CaCu_2O_{8+{\delta}}$ mesa containing a small number of intrinsic stacked Josephson junctions in a magnetic field. We fabricated mesa with an area of 40${\times}$40 ${\mu}$m$^2$ containing 3${\sim}$20 intrinsic junctions. We applied magnetic field perpendicular to He CuO$_2$ planes up to 5T. We observed flux-flow branches and flux-flow steps in the I-V characteristics which might be due to collective motion of Josephson vortices in the long junction limit. In a parallel field, critical current I$_c$ varies as I$_c$(B) ${\sim}$ exp(-B/B$_0$), where B$_0$ is about 2T, which is consistent with the theoretical model. DC and AC intrinsic Josephson effects are also discussed.

• Progress in Superconductivity
• /
• v.4 no.2
• /
• pp.104-108
• /
• 2003

We have measured the transport properties of $Bi_2$$Sr_2$$CaCu_2$$O_{8+d}$ (BSCCO) intrinsic Josephson junction mesa. Transport measurements with current flow along the c-axis, perpendicular to the layer of mesa showed multi-branch structures on the current-voltage characteristics. For single intrinsic junctions, the microwave radiation appears in the form of three different modes of oscillations, which include Josephson emission, nonequilibrium broad emission and sharp coherent microwave emission. Mutual phase interactions between two-mesas structures of BSCCO intrinsic Josephson junctions were studied. The results were explained within the framework of the Josephson plasma excitation model due to quasiparticle injection.n.

• 한국초전도학회:학술대회논문집
• /
• v.10
• /
• pp.9-14
• /
• 2000

We report on the novel nonequilibrium nlicrowave emission from quasiparticle-injected high-Tc superconductors. The phenomena have been observed for the current-injected YBCO/I/Au or BSCCO/I/Au thin-film tunnel junctions and BSCCO single-crystal intrinsic Josephson mesa junction samples. For the thin-film tunnel junctions, the emitted radiation appears as broadband. For the intrinsic BSCCO mesa samples, the radiation appears as three different modes of emissions depending on the bias point in the hysteretic current-voltage characteristics; Josephson-emission, nonequilibrium broad emission and sharp coherent microwave emission. The results were interpreted by the Josephson plasma excitation model due to quasiparticle injection.

• 한국초전도학회:학술대회논문집
• /
• v.13
• /
• pp.52-52
• /
• 2003

• 한국초전도학회:학술대회논문집
• /
• v.12
• /
• pp.37-37
• /
• 2002

• Progress in Superconductivity
• /
• v.7 no.1
• /
• pp.17-21
• /
• 2005

We report the oscillation of the Josephson vortex-flow resistance in the rectangular stacks of $Bi_{2}Sr_{2}CaCu_{2}O_{8+x}$(Bi-2212) intrinsic Josephson junctions (IJJs). Apiece of Bi-2212 single crystal containing a few tens of IJJs was sandwiched between two gold electrodes and fabricated into a rectangular shape with the typical lateral size of about $1.5{\times}10\;{\mu}m^2$, using e-beam lithography and focused ion-beam etching techniques. In a tesla-range magnetic field applied in parallel with the junction planes, the oscillation of the Josephson vortex flow resistance was observed at temperatures near 60 K. The oscillation results from the interplay between the triangular Josephson vortex lattice and the potential barrier at the boundary of a single crystal. The oscillatory magnetoresistance for different bias currents, external magnetic fields, and the tilt-angles provides useful information on the dynamics of the coupled Josephson-vortex lattice system.

• 한국초전도학회:학술대회논문집
• /
• v.14
• /
• pp.56-56
• /
• 2004

• 한국초전도학회:학술대회논문집
• /
• 2009.07a
• /
• pp.80-80
• /
• 2009

• 한국초전도학회:학술대회논문집
• /
• 2008.08a
• /
• pp.52-52
• /
• 2008