Min-Seok Park

Superconducting properties of well-shaped MgB2 single crystals

We report measurements of the transport and the magnetic properties of high-quality, sub-millimeter-sized

Hole carrier in MgB2 characterized by Hall measurements

{\mathrm{MgB}}_{2}

Effect of sintering temperature under high pressure on the superconductivity of MgB2

single crystals with clear hexagonal-plate shapes. The low-field magnetization and the magnetic hysteresis curves show the bulk pinning of these crystals to be very weak. The Debye temperature of

Temperature- and magnetic-field-dependent resistivity of MgB2 sintered at high-temperature and high-pressure condition

{\ensuremath{\Theta}}_{D}\ensuremath{\sim}1100 \mathrm{K},

Physical properties of ZnCNi3: comparison with superconducting MgCNi3

obtained from the zero-field resistance curve, suggests that the normal-state transport properties are dominated by electron-phonon interactions. The resistivity ratio between 40 K and 300 K was about 5, and the upper critical field anisotropy ratio was

Spectroscopic evidence for anisotropic s-wave pairing symmetry in MgB2

3.0\ifmmode\pm\else\textpm\fi{}0.2

Negligible effect of grain boundaries on the supercurrent density in polycrystalline MgB2

at temperatures around 32 K.

Prominent bulk pinning effect in the MgB 2 superconductor

The longitudinal resistivity (ρxx) and Hall coefficient (RH) were measured for MgB2 sintered under high pressure. We found that RH is positive like cuprate high-Tc superconductors, and decreases as the temperature increases for 40 K <T<300 K. The cotangent of the Hall angle was found to follow a+bT2 behavior from Tc to 300 K. At T=100 K, RH=4.1×10−11 m3/C from which the hole carrier density was determined to be 1.5×1023/cm3. This carrier density is 1–2 orders of magnitude larger than those of Nb3Sn and optimally doped YBa2Cu3Oy superconductors.

Strongly correlated s-wave superconductivity in the N-type infinite-layer cuprate.

We report on the effect of sintering temperature on the superconductivity of MgB2 pellets prepared under a high pressure of 3 GPa. The superconducting properties of the nonheated MgB2 were poor. However, as the sintering temperature increased, the superconducting properties were vastly enhanced, which was demonstrated by the narrow transition width for the resistivity and the low-field magnetization. The observed surface morphology using scanning electron microscopy showed that these changes were closely related to changes in the microscopic level such as the connectivity of the grains.

X-ray photoemission study of MgB 2

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 measurement was about 0.4 K, and the low-field magnetization showed a sharp superconducting transition with a transition width of about 1 K. The resistivity in the normal state roughly followed T2 behavior with smaller residual resistivity ratio (RRR) of 3 over broad temperature region above 100 K rather than reported T3 behavior with larger RRR value of ∼20 in the samples made at lower pressures. Also, the resistivity did not change appreciably with the applied magnetic field, which was different from previous report. These differences were discussed with the microscopic and structural change due to the high-pressure sintering.