TopPage学生の学会発表 > 05論文

2005 論文

2009/01/13(Tue) 10:07


1: Transport, magnetic, thermal and structural properties
  of the spinel compound CuTi2S4
Okada, H; Koyama, K; Watanabe, K

We have studied the transport, magnetic, thermal and structural properties of spinel compound CuTi2S4 using a high-quality polycrystalline sample. CuTi2 S4 shows simple metallic conductivity and the Pauli paramagnetism, and there is no structural phase transition down to 8.3 K. The magnetic susceptibility increases with decreasing temperature and begins to saturate below 50 K. The electronic specific heat coefficient and the Debye temperature are estimated to be 23.9 mJ(mol K 2) and 352 K, respectively. These physical properties of CuTi2S4 are probably attributed to narrow bands and high density of states of Ti 3d bands.

2: E-J Properties and Local Jc Distribution of
Practical Ag-Sheathed Bi2Sr2CaCu2O8 Tapes

K. Takahashi, S. Awaji, G. Nishijima and K. Watanabe
Superconductor Sci. Technol. 18 (2005) S223-S226.

E-J properties of the high-Tc superconductors are related to the distribution of the flux pinning strength and the local critical current density Jcl. From the previous result of Bi2212 thick films, we found that the distribution of the local Jc is much affected by microstructures, and the local Jc distribution becomes broad and asymmetric for well aligned plate-like Bi2212 grains. These microstructures are similar to the case of practical Ag sheathed Bi2212 tapes. In this study, we performed E-J measurements of practical Ag sheathed Bi2212 tapes at various temperatures and magnetic fields, and the local Jc distribution was investigated.