Equilibrium magnetic characteristics of high-Tc superconductors with allowance for the spatial distribution of the order parameter in the vortex cores. II. Vibrational contribution to the dynamic magnetic permeability

2001 ◽  
Vol 27 (2) ◽  
pp. 119-124 ◽  
Author(s):  
L. G. Mamsurova ◽  
K. S. Pigalskiy ◽  
W. V. Pogosov
Keyword(s):  
Spatial Distribution ◽  
Magnetic Permeability ◽  
Order Parameter ◽  
Magnetic Characteristics ◽  
High Tc Superconductors ◽  
High Tc ◽  
Vibrational Contribution

Ac Susceptibility Studies of the High Tc Superconductors: Dissipative Effects in La2.xSrxCuO4-Y and YBa2Cu3O7-Y Systems

1989 ◽  
Vol 169 ◽  
Author(s):  
Xinsheng Ling ◽  
M. E. Filipkowski ◽  
E. K. Heller ◽  
J. I. Budnick
Keyword(s):  
Grain Boundaries ◽  
Order Parameter ◽  
Ac Susceptibility ◽  
Similar Process ◽  
Charge Carrier Density ◽  
High Tc Superconductors ◽  
High Tc ◽  
Spatial Fluctuation ◽  
Dissipative Effects ◽  
Ceramic Samples

AbstractWe have studied the variation of dissipative effects with doping in the high Tc superconductors La2-xSrxCuO4-y and YBa2Cu3O7-y by studying the lossy component of ac susceptibility as a function of temperature. We find relatively strong excess losses at low temperature in both systems, which indicate stronger flux creep at grain boundaries, in lower level doped ceramic samples produced by a similar process. This effect is more significant in the La2-xSrxCuO4-y (214) system than in the YBa2Cu3O7-y(123) system. We suggest that the microscopic mechanisms of weakening of the order parameter in the grain boundaries may be different in the two systems. In the 214 system, as the charge carrier density in the CuO2 planes is reduced, the spatial fluctuation of the order parameter in the CuO2 planes is enhanced. In the 123 system, the initial removal of O from the sample, which weakens the coupling between planes and increases the spatial fluctuation of the order parameter between CuO2 planes. The grain boundaries are degraded in both systems. The degradation in the 214 samples is more significant than in the 123 samples.

Structural and Magnetic Characteristics of (Eu1-xGax) Ba2Cu3O7-δ High-Tc Superconductors

1997 ◽  
Vol 11 (13) ◽  
pp. 593-597 ◽  
Author(s):  
Iuliu Pop ◽  
Radu Redac ◽  
Gheorghe Borodi ◽  
Virgil Ioncu
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Tetragonal Structure ◽  
Magnetic Characteristics ◽  
High Tc Superconductors ◽  
High Tc ◽  
Gallium Concentration ◽  
Paramagnetic Region ◽  
Diamagnetic Transition

The high-T c ( Eu 1-x Ga x) Ba 2 Cu 3 O 7-δ superconductors with x=0, 0.01, 0.02, 0.03, 0.06 and 0.09 were synthesized by a ceramic technique. The gallium concentration dependence of the lattice parameters was determined. A transition from orthorhombic toward tetragonal structure was relevated for the most gallium concentrated sample. The temperature dependence of the magnetic susceptibility pointed out the diamagnetic transition at 78 and 80 K. In the paramagnetic region the magnetic susceptibility exhibits anomal temperature dependence.

On the Origin of Zero-Bias Conductance Peak in High-Tc Superconductors

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3027-3030
Author(s):  
Alexander B. Nazarenko ◽  
Ernst A. Pashitskii ◽  
Alexander E. Pashitskii
Keyword(s):  
Elastic Scattering ◽  
Order Parameter ◽  
Magnetic Impurities ◽  
High Tc Superconductors ◽  
Zero Bias ◽  
High Tc ◽  
Conductance Peak ◽  
Wave Symmetry ◽  
Zero Bias Conductance ◽  
D Wave

We show that the zero-bias conductance peak observed in tunnel and point junctions of cuprates can be a consequence of "unitary" elastic scattering of the carriers by non-magnetic impurities in the vicinity of the junction interface and d-wave symmetry of the order parameter.

Pair Symmetry and Degree of Gap Depression at S-I Interfaces in HTS Josephson Junctions

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1301-1306
Author(s):  
G. A. Ummarino ◽  
R. S. Gonnelli ◽  
C. Bravi ◽  
Masumi Inoue
Keyword(s):  
Josephson Junctions ◽  
Order Parameter ◽  
Reference Value ◽  
High Tc Superconductors ◽  
S Wave ◽  
General Reference ◽  
High Tc ◽  
Wave Symmetry ◽  
Set Up ◽  
D Wave

A new possible indirect way of testing pair symmetry in high-Tc superconductors has been set up. The degree of intrinsic gap depression at Superconductor-Insulator [S-I] interfaces required to match Ic(T)Rn(T) data in HTS Josephson junctions depends on the pair symmetry of the material itself, so that an higher fraction of d-wave symmetry for the order parameter requires less gap depression, while an higher fraction of s-wave corresponds to a larger degree of gap depression. In order to obtain a general reference value for the intrinsic amount of gap depression at S-I interfaces the de Gennes condition has been used, and resulting reduced Ic(T)Rn(T) data have been calculated in the framework of a mixed (s+id)-wave pair symmetry for the depressed order parameter ranging from pure s to pure d-wave. This model has been tentatively applied to two junctions' made of very different HTSs: YBCO and BKBO, yielding a result of almost pure d-wave for YBCO and of pure s-wave for BKBO.

Raman scattering line shapes as a probe of the order parameter symmetry in high — Tc superconductors

1994 ◽  
Vol 235-240 ◽  
pp. 1077-1078
Author(s):  
K.P. Jain ◽  
A.K. Shukla ◽  
R. Ramakumar ◽  
Ratnamala Chatterji ◽  
M. Fukutomi
Keyword(s):  
Raman Scattering ◽  
Order Parameter ◽  
High Tc Superconductors ◽  
High Tc ◽  
Line Shapes ◽  
Parameter Symmetry ◽  
Order Parameter Symmetry

CRITICAL TEMPERATURE OF HIGH-Tc SUPERCONDUCTORS AND BOUNDARY CONDITIONS IN GINZBURG-LANDAU THEORY

2009 ◽  
Vol 23 (20n21) ◽  
pp. 4269-4276 ◽  
Author(s):  
A. LYKOV
Keyword(s):  
Boundary Condition ◽  
Critical Temperature ◽  
Order Parameter ◽  
Cuprate Superconductors ◽  
Landau Theory ◽  
Structural Elements ◽  
High Tc Superconductors ◽  
Ginzburg Landau ◽  
High Tc ◽  
Insulating Properties

New boundary condition for the order parameter in the Ginzburg-Landau theory is applied to the case of CuO 2 planes which are the main structural elements responsible for superconductivity in high-Tc superconductors. It was found that the order parameter in these superconductors is significantly depressed in the CuO 2 planes. As a result, this boundary condition to the GL equations is found to limit the critical temperature of high-Tc superconductors. Thus, in order to increase Tc of cuprate superconductors, the number of CuO 2 planes that are within a short distance of each other in unit cell or insulating properties of the layers located in the vicinity to the CuO 2 planes should be increased.

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