Anisotropic superconducting properties of high-Tc Tl-Ba-Ca-Cu-O single crystal
1989; Elsevier BV; Volume: 159; Issue: 3 Linguagem: Inglês
10.1016/0921-4534(89)90384-5
ISSN1873-2143
AutoresM. Iwasaki, Norio Kobayashi, Masae Kikuchi, Tsuyoshi Kajitani, Yasuhiko Syono, Yoshio Mutô, Satoru Nakajima,
Tópico(s)Superconducting Materials and Applications
ResumoThe electrical resistance was measured on a Tl-Ba-Ca-Cu-O single crystal. From X-ray diffraction the composition of the sample is expected to be Tl:Ba:Ca:Cu=1:2:1:2. The superconducting transition temperature Tc is 106 K. The upper critical field Hc2 shows anisotropy, that is, (-dHc2/dT)Tc for H⊥c-axis and for H∥c-axis are 1.9 T/K and 0.2 T/K, respectively. The ratio of the former to the latter is 9.5. The low resistance part in the transition shows a thermally activated temperature dependence. The activation energy U0 estimated from its temperature dependence is also anisotropic. The U0 values for H⊥c-axis and H∥c-axis are about 4000 K and 1200 K at 0.5 T, respectively, and depend on applied magnetic fields. The anisotropy of the superconducting properties is intermediate in magnitude for this compound compared with the other high-Tc oxides such as YBa2Ca3O7−δ and Bi2Sr2CaCu2Oy.
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