论文信息 - Absolute measurement of penetration depth in a superconducting film by the two-coil technique

Absolute measurement of penetration depth in a superconducting film by the two-coil technique

A two-coil mutual-inductance apparatus that is optimized to allow for the measurement of the absolute value of penetration depth λ in superconducting films is described. Nb films with thickness d ranging from 20 to 90 nm are used to illustrate the measurement. For a 70-nm-thick Nb film at 4.2 K, with d/λ∼0.6, the uncertainty in the measured λ is about ±2.3%. From the results on the Nb film series, we show that a satisfactory determination of the absolute value of λ is possible for these films with d/λ<0.95.

S. P. Zhao | Q. S. Yang | G H Chen | Reng Wang

[1] A. Pippard. Magnetic field penetration through a superconducting film , 1994 .

[2] T. Geballe,et al. Tc depression in thin Nb films , 1985 .

[3] J. Cuomo,et al. ELECTRICAL CHARACTERISTICS OF rf-SPUTTERED SINGLE-CRYSTAL NIOBIUM FILMS. , 1972 .

[4] D. K. Finnemore,et al. Superconducting Properties of High-Purity Niobium , 1966 .

[5] Chen,et al. Thickness dependence on the superconducting properties of thin Nb films. , 1994, Physical review. B, Condensed matter.

[6] Richard E. Howard,et al. Penetration depths of high Tc films measured by two‐coil mutual inductances , 1988 .

[7] Barber,et al. Observation of the superconducting proximity effect from kinetic-inductance measurements. , 1991, Physical review. B, Condensed matter.

[8] Michael Tinkham,et al. Introduction to Superconductivity , 1975 .

[9] Greene,et al. Greene, Krusin-Elbaum, and Malozemoff reply. , 1989, Physical review letters.

[10] T. Lemberger,et al. Numerical modeling of a two‐coil apparatus for measuring the magnetic penetration depth in superconducting films and arrays , 1996 .

[11] R. Howard,et al. Renormalization of the mean-field superconducting penetration depth in epitaxial YBa2Cu3O7 films. , 1988, Physical review letters.