상세정보
학술지
Temperature dependences of the surface resistance and the diamagnetic shielding susceptibility at T/sub c/-T/spl Lt/T/sub c/ for high-T/sub c/ superconductors
- 발행일
- 200103
- 출처
- IEEE Transactions on Applied Superconductivity, v.11 no.1, pp.3415-3418
- ISSN
- 1051-8223
- 출판사
- IEEE
- 협약과제
- 01MB1400, 밀리미터파 고온초전도 믹서, 강광용
- 초록
- At Tc - T << Tc (i.e., near Tc), in order to demonstrate the conduction mechanism and temperature dependencies of the diamagnetic-shielding susceptibility and the penetration depth, we fabricated Ba1-xKxBiO 3 (BKBO) thin films and measured the energy gap by tunnel effect and shielding susceptibilities which are compared with those measured for BKBO and YBCO single crystals. The shielding susceptibilities for BKBO and YBCO crystals well-fit ??(T)/??(0) = 1 - exp(-2??(T)/kBT), while that for the BKBO film follows ??(T)/??(0) = (1 - T/Tc) which may not be intrinsic. The exponential decrease of the susceptibilities near Tc indicates that the conduction mechanism is hopping. The energy gaps are observed as 2??(0) = (3.5짹0.1)kBTc for the BKBO film by the tunnel effect, 2??(0) = (3.9짹0.1)kBTc for the BKBO single crystal, and 2??(0) = (8짹0.2)kBTc for the YBa2Cu3O7 single crystal. Furthermore, for microwave device applications of superconductors, at Tc - T < < Tc, the surface resistance Rs(T)≈?닖?됌?0/2/?긪+ (?긯(0)-?긪)f(T) is derived from the surface impedance at ?됍꼝r <<1, where ?긯(0) and ?긪 are the conductivities of the superconducting state and the normal state, respectively, and f(T) = ??(T)/??(0) = (1 - exp(-2??(T)/kBT)).
- KSP 제안 키워드
- As 2, At t, Energy gap, Normal state, Single crystal, Superconducting state, Surface impedance, conduction mechanism, device applications, microwave devices, penetration depth