Very high resolution measurement of the penetration depth of superconductors by a novel single-coil inductance technique

We describe a novel single-coil mutual inductance technique for measuring the magnetic penetration depth λ of superconductors at 2–4 MHz as a function of temperature in the 4–100 K range. We combine a single-coil configuration with a high-stability marginal oscillator; this enables us to measure the absolute value of λ on both bulk samples and thin films with very high resolution (δλ=10 pm) and a precision of 30 nm. As example of application, we report measurements on NbTi bulk samples and Nb films. This contactless technique is suited for probing the superconducting properties of samples over large surfaces.

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

[2]  M. Obolensky,et al.  Anomalous temperature dependence of the electromagnetic penetration depth of Y1Ba2Cu3O7−δ crystals , 1994 .

[3]  E. M. Forgan,et al.  Observation of a square flux-line lattice in the unconventional superconductor Sr2RuO4 , 1998, Nature.

[4]  Mathieu,et al.  Continuum electrodynamics of type-II superconductors in the mixed state: The dc and ac response. , 1996, Physical review. B, Condensed matter.

[5]  Daemen,et al.  Superconducting gap anisotropy caused by a spin-density wave. , 1988, Physical review letters.

[6]  Wu,et al.  Measurements of magnetic screening lengths in superconducting Nb thin films by polarized neutron reflectometry. , 1995, Physical review. B, Condensed matter.

[7]  Morgan,et al.  Precision measurements of the temperature dependence of lambda in YBa2Cu3O6.95: Strong evidence for nodes in the gap function. , 1993, Physical review letters.

[8]  J. Claassen,et al.  Optimizing the two-coil mutual inductance measurement of the superconducting penetration depth in thin films , 1997 .

[9]  G. Gu,et al.  Bi 2 Sr 2 CaCu 2 O 8 + δ Bicrystal c -Axis Twist Josephson Junctions: A New Phase-Sensitive Test of Order Parameter Symmetry , 1999 .

[10]  B. Mühlschlegel.  Die thermodynamischen Funktionen des Supraleiters , 1959 .

[11]  Y. Maeno,et al.  Extremely Strong Dependence of Superconductivity on Disorder in Sr2RuO4 , 1998 .

[12]  A. Gauzzi,et al.  Importance of out-of-plane dispersion of the excitation spectrum of superconducting bilayers with Josephson coupling , 1996 .

[13]  S. Anlage,et al.  MICROWAVE SURFACE IMPEDANCE OF PROXIMITY-COUPLED SUPERCONDUCTING (NB)/SPIN-GLASS (CUMN) BILAYERS , 1998, cond-mat/9811347.

[14]  B. Jeanneret,et al.  Inductive conductance measurements in two-dimensional superconducting systems , 1989 .

[15]  Qi Li,et al.  Observation of Berezinski-Kosterlitz-Thouless transition in PrYBaCuO/YBaCuO/PrYBaCuO trilayers , 1996, Photonics West.

[16]  G. White.  Experimental techniques in low-temperature physics , 1968 .

[17]  K. Andres,et al.  Anomalous temperature dependence of the magnetic field penetration depth in superconducting UBe13 , 1986 .

[18]  A. Hebard,et al.  Evidence for the Kosterlitz-Thouless transition in thin superconducting aluminum films , 1980 .

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

[20]  V. Gasparov,et al.  TEMPERATURE DEPENDENCE OF THE PENETRATION DEPTH IN EPITAXIAL Y1BA2CU3O7-X THIN FILMS , 1991 .

[21]  Sun,et al.  Direct imaging of integer and half-integer Josephson vortices in high-Tc grain boundaries. , 1996, Physical review letters.

[22]  M. Peiniger,et al.  The effective microwave surface impedance of high Tc thin films , 1990 .

[23]  P. Probst,et al.  Marginal oscillator optimized for radiofrequency size effect measurements , 1976 .