A. Harada

Quasi-Two-Dimensional Fermi Surfaces and Coherent Interlayer Transport in KFe2As2

We report the results of the angular-dependent magnetoresistance oscillations (AMROs), which can determine the shape of bulk Fermi surfaces (FSs) in quasi-two-dimensional (Q2D) systems, in a highly hole-doped Fe-based superconductor

Effects of Pressure and Magnetic Field on the Pressure-Induced Superconductivity in EuFe2As2

{\mathrm{KFe}}_{2}{\mathrm{As}}_{2}

High-Pressure Electrical Resistivity Measurements of EuFe2As2 Single Crystals

with

Sample size dependence of excess resistance near critical field in mesoscopic superconducting Al disk

{T}_{c}\ensuremath{\approx}3.7\text{ }\text{ }\mathrm{K}

Fermi surface and interlayer transport in the two-dimensional magnetic organic conductor (Me-3,5-DIP)[Ni(dmit)2]2

. From the AMROs, we determined the two Q2D FSs with rounded-square cross sections, correspond to 12% and 17% of the first Brillouin zone. The rounded-squared shape of the FS cross section is also confirmed by the analyses of the interlayer transport under in-plane fields. From the obtained FS shape, we infer the character of the

Interplay between magnetism and conductivity in the one-dimensional organic conductor TPP[Fe(Pc)(CN)2]2

3d

Large energy dissipation due to vortex dynamics in mesoscopic Al disks

orbitals that contribute to the FSs.

Non-linear current-voltage characteristics in α-(BEDT-TTF)2I3

We have performed electrical resistivity measurements of EuFe2As2 under hydrostatic pressures (P) up to 3.2 GPa and magnetic fields up to 15 T. In zero field, the superconducting (SC) ground state with a sharp transition to zero resistivity, indicative of bulk superconductivity, emerges at Tc ~ 30 K in a pressure range from 2.5 GPa to ~ 3.0 GPa. Under applied field of 15 T, the SC transition is suppressed to lower temperatures with increasing pressure, suggesting that the application of pressure reduces the upper critical field Bc2 for the P-induced superconductivity. Meanwhile, the antiferromagnetic (AF) order of the Eu2+ moments survives up to 3.2 GPa, the highest pressure in the experiments, with no significant change in the AF ordering temperature and the magnetic field effect.

Non-linear currentvoltage characteristics in a-(BEDT-TTF) 2I 3

High-pressure electrical resistivity measurements up to 3.0 GPa have been performed on EuFe2As2 single crystals with residual resistivity ratios RRR= 7 and 15. At ambient pressure, a magnetic /structural transition related to FeAs-layers is observed at T0 = 190K and 194 K for samples with RRR= 7 and 15, respectively. Application of hydrostatic pressure suppresses T0, and then induces similar superconducting behavior in the samples with different RRR values. However, the critical pressure ~2.7 GPa, where T0 → 0, for the samples with RRR= 15 is slightly but distinctly larger than ~2.5 GPa for the samples with RRR = 7.

NQR Study of Uranium Ternary Compound UCu_2Sn

We report the size dependence of superconducting transition in mesoscopic Al disks with 1.0, 0.7, and 0.4? m in diameter performed by resistance measurements under magnetic field. All the samples show excess resistance peaks near Hc2, which are 3 ~ 6 times larger than normal state resistance Rn, whereas there are no resistance peaks at H = 0. We find that the resistance peak rapidly increases and becomes the largest at the magnetic field just below the transition of vorticity L : 0 ? 1 with no relation to the sample size. The resistance peak, which shows the presence of large energy dissipation, would be caused by characteristic vortex dynamics confined in the small geometries.