2005　論文

2005年

1: Transport, magnetic, thermal and structural properties
　　of the spinel compound CuTi₂S₄
Okada, H; Koyama, K; Watanabe, K
JOURNAL OF ALLOYS AND COMPOUNDS 403 (2005)1-2, 34-37

Abstract
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 J_c Distribution of
Practical Ag-Sheathed Bi₂Sr₂CaCu₂O₈ Tapes
K. Takahashi, S. Awaji, G. Nishijima and K. Watanabe
Superconductor Sci. Technol. 18 (2005) S223-S226.

Abstract
E-J properties of the high-T_c superconductors are related to the distribution of the flux pinning strength and the local critical current density J_cl. From the previous result of Bi2212 thick films, we found that the distribution of the local J_c is much affected by microstructures, and the local J_c 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 J_c distribution was investigated.