Microstructure and Temperature Dependence of Microwave Penetration Depth of Ag-YBa2Cu3O7-δ Thin Films

1998 ◽  
Vol 526 ◽  
Author(s):  
Davinder Kaur ◽  
R. Pinto
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Penetration Depth ◽  
Impurity Scattering ◽  
Bcs Theory ◽  
S Wave ◽  
Microstrip Resonator ◽  
Wave Pairing ◽  
Film Microstructure ◽  
D Wave

AbstractWe report the measurements of the magnetic penetration depth λ(T) of Ag-doped YBa2Cu3O7-δ (YBCO) thin films in the film thickness range 1500-4000A and temperature range 18-88K. The films are insitu grown by laser ablation on LaAlO3 <100> single crystal substrates. The penetration depth measurements are performed by microstrip resonator technique. A correlation of λ(T) with the film microstructure observed with Atomic Force Microscopy has shown that λ(T) depends critically on the film microstructure. Temperature dependence of λ(T) has also been studied for best quality films.The experimental results are discussed in terms of BCS theory (s-wave pairing) and d-wave Pairing with and without impurity scattering. The results are found to be best fitted to the d-wave model in dirty limit with impurity scattering. Near Tc, we have also compare the (3D) XY critical regime and the Ginzburg-Landau (GL) behaviour.

Magnetic Penetration Depth Measurements and Inhomogeneity in YBa2Cu3O7−δ Superconducting Thin Films

1990 ◽  
Vol 195 ◽  
Author(s):  
Steven M. Anlage ◽  
Brian W. Langley ◽  
Jurgen Halbritter ◽  
Chang-Beom Eom ◽  
Neil Switz ◽  
...  
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Penetration Depth ◽  
Exponential Decay ◽  
Power Law ◽  
Low Temperatures ◽  
Bcs Theory ◽  
Magnetic Penetration Depth ◽  
Microstrip Resonator ◽  
Magnetic Penetration

ABSTRACTThe microstrip resonator technique has been applied to study the temperature dependence of the magnetic penetration depth in high quality YBa2Cu3O7−δ thin films. The temperature dependence at low temperatures comes out directly from measured data, with no assumptions about transmission line geometry, dielectric properties, or a model for the temperature dependence of the penetration depth. One can interpret the data in terms of either an exponential decay of λ(T) at low temperatures or as a power law decay. The energy gaps obtained from the exponential decay at low temperature are found to be significantly smaller than weak coupled BCS theory and power-law exponents are in the range of 1.3 to 3.2. These results will be discussed in terms of microscopic theories and the possibility that materials properties dominate the measurement.

scholarly journals STUDY OF THE ELECTRODYNAMIC RESPONSE OF MgB2 SINTERED PELLETS AND THIN FILMS

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1599-1603
Author(s):  
A. ANDREONE ◽  
E. DI GENNARO ◽  
G. LAMURA ◽  
M. SALLUZZO ◽  
J. LE COCHEC ◽  
...  
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Penetration Depth ◽  
Surface Impedance ◽  
Experimental Results ◽  
S Wave ◽  
Critical Temperatures ◽  
Depth Data ◽  
Single Coil ◽  
Magnetic Penetration

We present a number of experimental results on the temperature dependence of the magnetic penetration depth λ and on the temperature and field dependence of the microwave surface impedance Z s =R s +iX s in both pellets and thin films of MgB2 , exhibiting critical temperatures ranging between 26 and 38 K. Accurate measurements of Z s (H,T) were performed by means of a sapphire dielectrically loaded cavity operating in the microwave region (20 GHz). The study of λ(T) was carried out employing a single coil mutual inductance technique in the MHz region. An anisotropic s-wave BCS model can account for the temperature dependence experimentally observed in the penetration depth data of the best films, confirming previous reports on the conventional nature of superconductivity in diborides. On the contrary, films having a reduced value of the critical temperature and pellets show no evidence of saturation, and the experimental results strictly follow a quadratic dependence down to the lowest temperatures. We explain this behavior with the presence of metallic Mg inclusions that may locally depress the gap. The study of the surface impedance versus temperature and field shows also that the source of microwave loss can be markedly different, depending on the structural and transport properties of the samples.

Temperature dependence of the magnetic penetration depth in Nb, NbCN and YBa2Cu3O7-δ thin films

1991 ◽  
Vol 169 (1-4) ◽  
pp. 671-672 ◽  
Author(s):  
S.M. Anlage ◽  
B.W. Langley ◽  
G. Deutscher ◽  
R.W. Simon ◽  
J.M. Murduck ◽  
...  
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Penetration Depth ◽  
Magnetic Penetration Depth ◽  
Magnetic Penetration

CDW AND SDW MEDIATED PAIRING INTERACTIONS

1987 ◽  
Vol 01 (03n04) ◽  
pp. 687-695 ◽  
Author(s):  
N.E. Bickers ◽  
D.J. Scalapino ◽  
R.T. Scalettar
Keyword(s):  
S Wave ◽  
Wave Pairing ◽  
Pairing Interactions ◽  
D Wave

Pairing near CDW and SDW metal-semiconductor transitions is analyzed for a 2-D lattice within an RPA approximation. We find that s-wave pairing can occur near the CDW transition provided the on-site U is not too large, while d-wave pairing occurs near an SDW transition.

Temperature dependence of the magnetic penetration depth in the high-TcsuperconductorBa2YCu3O9−δ: Evidence for conventionals-wave pairing

1987 ◽  
Vol 36 (4) ◽  
pp. 2386-2389 ◽  
Author(s):  
D. R. Harshman ◽  
G. Aeppli ◽  
E. J. Ansaldo ◽  
B. Batlogg ◽  
J. H. Brewer ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Penetration Depth ◽  
Magnetic Penetration Depth ◽  
Wave Pairing ◽  
Magnetic Penetration

Neutron Diffraction by the Flux Line Lattice in YBa2Cu3O7−δ Single Crystals

1997 ◽  
Vol 30 (5) ◽  
pp. 571-574 ◽  
Author(s):  
G. Brandstätter ◽  
H. W. Weber ◽  
T. Chattopadhyay ◽  
R. Cubitt ◽  
H. Fischer ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Flux Line ◽  
Impurity Scattering ◽  
Bcs Theory ◽  
Line Lattice ◽  
Electron Pairs ◽  
Flux Line Lattice ◽  
Wave Pairing ◽  
Integrated Intensity ◽  
Magnetic Penetration

Small-angle neutron diffraction was used to image the mixed state in a large superconducting YBa2Cu3O7−δ single crystal. The flux line lattice was observed in fields up to 2 T at various temperatures from 2.4 to 80 K. The integrated intensity I of the (10) reflection was calculated as a function of temperature for three different fields (0.8, 1 and 2 T). From these I(T) curves, the magnetic penetration depth λ(T) was obtained on an absolute scale. This quantity is of particular interest, since it provides information on the nature of the pairing mechanism in the superconductor, i.e. the symmetry of the wavefunction of the electron pairs. The results are discussed in terms of BCS theory (s-wave pairing) and of d-wave pairing with and without impurity scattering.

THE EFFECT OF THE INTERACTION BETWEEN THE FILMS AND THE SUBSTRATES ON THE MICROWAVE PROPERTIES Of YBCO THIN FILMS

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3224-3226
Author(s):  
LIBIN SHI ◽  
YUNFEI WANG ◽  
YUYANG KE ◽  
QUANWU WANG ◽  
ZHEN ZHANG ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Resonant Frequency ◽  
Temperature Dependence ◽  
Surface Resistance ◽  
Microwave Properties ◽  
Microwave Surface Resistance ◽  
Microstrip Resonator ◽  
Lower Temperature ◽  
Xrd Patterns

The microwave properties of YBa 2 Cu 3 O 7- x / LaAlO 3 (YBCO/LAO) and YBa 2 Cu 3 O 7- x / MgO (YBCO/MgO) thin films have been investigated by microstrip resonator technique. The penetration depth λ0(0 K ) and the microwave surface resistance Rs can be obtained by analyzing the experimental data of the temperature dependence of resonant frequency, unload quality factor of the microstrip resonator. The stress in the two thin films can be obtained from their XRD patterns. The result shows that the stronger stress in YBCO/LAO thing film makes it have larger microwave surface resistance at lower temperature.

TUNNELING SPECTROSCOPY OF THE ELECTRON-DOPED CUPRATE SUPERCONDUCTOR Pr2-xCexCuO4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3175-3175
Author(s):  
A. BISWAS ◽  
P. FOURNIER ◽  
V. N. SMOLYANINOVA ◽  
H. BALCI ◽  
J. S. HIGGINS ◽  
...  
Keyword(s):  
Normal State ◽  
Cuprate Superconductors ◽  
Point Contact ◽  
Tunneling Spectroscopy ◽  
Pairing Symmetry ◽  
S Wave ◽  
Zero Bias ◽  
Wave Pairing ◽  
Wave Symmetry ◽  
D Wave

The properties of electron(n)-doped cuprate superconductors show significant deviations from those of their hold(p)-doped counterparts. Experiments prior to 2000 suggested an s-wave pairing symmetry as opposed to d-wave pairing symmetry in hole-doped cuprates. Recent experiments have suggested that n-doped cuprates have a d-wave pairing symmetry. However tunneling spectroscopy of these materials have not revealed a zero bias conductance peak (ZBCP), which is a classic signature of d-wave symmetry. We present the first tunneling spectroscopy data on n-doped Pr 2-x Ce x CuO 4 (PCCO) using point contact junctions which show a systematic evolution of the ZBCP. This method of junction fabrication is important as it allows the barrier strength between the normal and the superconducting electrodes to be varied. We show that this is essential to observing the ZBCP. The n-doped cuprates have a low Tc (~25 K ) and Hc2 (~10 T ). The low Hc2 enables us to obtain the normal state in PCCO at low temperatures. We have used this to probe the density of states in the normal state of PCCO. We observe an anomalous gap even in the normal state.1 This normal state gap (NSG) becomes smaller on the over-doped side. We discuss the behavior of this NSG in the context of the pseudogap which has been observed in hole-doped cuprates.

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