Transport Phenomena in the Mixed and Normal State of (Bi1.6Pb0.4)Sr2Ca2(Cu1-xFex)3Oy Epitaxial Thin Films

1998 ◽  
Vol 12 (25n26) ◽  
pp. 1081-1088 ◽  
Author(s):  
G. Ilonca ◽  
A. V. Pop ◽  
D. Benea ◽  
C. Lung ◽  
M. Lachescu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Normal State ◽  
Landau Theory ◽  
Upper Critical Field ◽  
Time Dependent ◽  
Epitaxial Thin Films ◽  
Critical Temperatures ◽  
Seebeck Coefficients ◽  
Hall Effects

We had performed a study on magnetoresistivity, Seebeck, Nernst and Hall effects in the mixed and normal state for Bi2223 thin films in magnetic fields between 0 and 5 T and in the temperature range 5–300 K. The critical temperatures, the Hall concentration, the Nernst and Seebeck coefficients depend strongly on the iron content in the samples. From our experimental data in the mixed state and fluctuation regime, the upper critical field slope (dBc2/dT )=-2:55 T/K was obtained, corresponding to ab-plane coherence length ξab=14 Å. The experimental data are in agreement with the predictions of the time-dependent Ginsburg–Landau theory.

TRANSPORT PHENOMENA IN THE MIXED STATE OF (Bi1.6Pb0.4) Sr2Ca2 (Cu1-xGax)3Oy BULK MATERIALS

2001 ◽  
Vol 15 (23) ◽  
pp. 1041-1046
Author(s):  
G. ILONCA ◽  
A. V. POP ◽  
G. STIUFIUC ◽  
R. STIUFIUC ◽  
C. LUNG
Keyword(s):  
Mixed State ◽  
Landau Theory ◽  
Solid State Reaction Method ◽  
Power Coefficient ◽  
Bulk Materials ◽  
Critical Temperatures ◽  
Conventional Solid State Reaction ◽  
Ginzburg Landau ◽  
Seebeck Coefficients ◽  
Hall Effects

We have performed a study of magnetoresistivity, Seebeck, Nernst and Hall effects in the mixed state and in the fluctuation regime above T c 0 for Bi:2223 bulk doped with Ga (0 ≤ x ≤ 0.05), prepared by the conventional solid state reaction method, in magnetic fields between 0 and 5 T and in the temperature range 5–120 K. It was found that critical temperatures, the Hall concentration, and the Nernst and Seebeck coefficients depend strongly on the Ga contents in the samples. The Hall resistivity ρxy showed a sign anomaly in the mixed state and scaled with longitudinal resistivity ρxx with a power coefficient β ≅ 2. The experimental data are in agreement with the predictions of the time-dependent Ginzburg–Landau theory.

ANOMALOUS NORMAL STATE PROPERTIES OF UNDERDOPED Bi 2212 THIN FILMS

2004 ◽  
Vol 18 (15) ◽  
pp. 2209-2214
Author(s):  
G. STIUFIUC ◽  
R. STIUFIUC ◽  
E. MACOCIAN ◽  
H. RAFFY ◽  
G. ILONCA
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Excitation Spectrum ◽  
Normal State ◽  
Characteristic Temperature ◽  
Epitaxial Thin Films ◽  
Normal State Properties ◽  
Upward Curvature ◽  
Significant Change

We investigate the effect of the opening of the pseudogap on the temperature dependence of the in-plane resistivity ρab(T) for Bi 2212 epitaxial thin films having different oxygen contents. Using successive annealing treatments we were able to bring the films from a maximally overdoped state (characterized by a T c of 63 K) to a strongly underdoped state (T c <10 K ). We also observed a significant change in the temperature dependence of the in-plane resistivity ρab(T). This dependence presents two major characteristics: for the overdoped sample we observed an upward curvature from linearity while for underdoped samples we observed a downturn from linearity starting from a characteristic temperature T* which will be associated with the opening of the pseudogap in the excitation spectrum.

THE UPPER CRITICAL FIELD OF THIN FILMS OF TWO-BAND SUPERCONDUCTORS: AN APPLICATION TO MgB2

2004 ◽  
Vol 18 (30) ◽  
pp. 1525-1531 ◽  
Author(s):  
I. N. ASKERZADE
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Temperature Dependence ◽  
Critical Field ◽  
Qualitative Agreement ◽  
Magnesium Diboride ◽  
Upper Critical Field ◽  
Ginzburg Landau

Temperature dependence of the upper critical field [Formula: see text] of thin films of two-band superconductors is studied using the two-band Ginzburg–Landau (G–L) theory. The results are shown to be in qualitative agreement with experimental data for the superconducting magnesium diboride MgB 2 films.

Upper Critical Field and Irreversibility Line in Bi2Sr2CuO6+δ/CaCuO2 Superconducting Superlattices Obtained by MBE

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2767-2772
Author(s):  
Matteo Salvato ◽  
Carmine Attanasio ◽  
Gerardina Carbone ◽  
Rosalba Fittipaldi ◽  
Tiziana Di Luccio ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Thin Films ◽  
Phase Diagrams ◽  
Applied Magnetic Field ◽  
Three Dimensional ◽  
Upper Critical Field ◽  
Resistivity Measurements ◽  
T Phase ◽  
The Magnetic Field

Resistivity measurements in external applied magnetic field up to 8.5T have been performed on Bi2Sr2CuO6+δ/CaCuO2 superconducting superlattices obtained by MBE. The magnetic field (H) vs. temperature (T) phase diagrams have been determined and the experimental data have been compared with that obtained in the case of Bi2Sr2CuO6+δ thin films deposited with the same technique. A reduction of the anisotropy has been obtained in the case of the superlattices with respect to the case of Bi2Sr2CuO6+δ thin films and a three dimensional behavior has been observed by paraconductivity measurements.

Normal-state transport parameters of epitaxial thin films ofYBa2Cu3O7−δ

1988 ◽  
Vol 38 (4) ◽  
pp. 2472-2476 ◽  
Author(s):  
H. L. Stormer ◽  
A. F. J. Levi ◽  
K. W. Baldwin ◽  
M. Anzlowar ◽  
G. S. Boebinger
Keyword(s):  
Thin Films ◽  
Normal State ◽  
Epitaxial Thin Films ◽  
Transport Parameters

ANGULAR DEPENDENCE OF UPPER CRITICAL FIELD FOR THE TWO-BAND SUPERCONDUCTOR Lu2Fe3Si5

2010 ◽  
Vol 24 (12) ◽  
pp. 1185-1190 ◽  
Author(s):  
MINXIA LIU ◽  
HAI HUANG
Keyword(s):  
Experimental Data ◽  
Angular Dependence ◽  
Critical Field ◽  
Landau Theory ◽  
Upper Critical Field ◽  
Ginzburg Landau ◽  
Theoretical Results ◽  
Good Agreement

Based on the two-band Ginzburg–Landau theory, we study the angular dependence of the upper critical field for the superconducting crystal Lu 2 Fe 3 Si 5. When θ=0 and θ=π/2, the theoretical results are in good agreement with the experimental data. Hence, the results support the existence of two-gap superconductivity in Lu 2 Fe 3 Si 5, previously suggested from experiments.

BANDGAP RENORMALIZATION DUE TO HIGH-DENSITY CARRIERS IN ZnO EPITAXIAL THIN FILMS

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3737-3740 ◽  
Author(s):  
AISHI YAMAMOTO ◽  
TAKEO KIDO ◽  
TAKENARI GOTO ◽  
YEFAN CHEN ◽  
TAKAFUMI YAO
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Correlation Energy ◽  
Optical Gain ◽  
High Density ◽  
Gain Spectrum ◽  
Experimental Results ◽  
Bandgap Energy ◽  
Epitaxial Thin Films

Renormalized bandgap energy due to high-density carriers in ZnO is calculated and compared with our experimental results. Two different reported treatments for the correlation energy are employed for the calculation, and we prove that Beni and Rice's model sufficiently explains the experimental data. Furthermore, we calculate optical gain spectrum, which reproduces well the experimental data.

Fe3O4 Epitaxial Thin Films and Heterostructures: Magnetotransport and Magnetic Properties

2010 ◽  
Vol 67 ◽  
pp. 82-91 ◽  
Author(s):  
Julia Orna ◽  
Luis Morellón ◽  
Pedro Algarabel ◽  
José M. De Teresa ◽  
Amalio Fernández-Pacheco ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Moment ◽  
Epitaxial Films ◽  
Epitaxial Thin Films ◽  
Magnetic Characterization ◽  
Hall Effects ◽  
Wide Range ◽  
Epitaxial Heterostructures

In this article, we review our recent research on Fe3O4 epitaxial thin films and Fe3O4/MgO/Fe epitaxial heterostructures. More specifically, we report on the magnetotransport properties of Fe3O4 epitaxial films in a wide range of film thicknesses and temperatures, focusing on the anomalous, planar and ordinary Hall effects. We also summarize our insight on the origin of the enhanced magnetic moment found in ultra-thin magnetite films (thickness t < 5 nm). Finally, our work on the growth, and structural and magnetic characterization of heteroepitaxial Fe3O4/MgO/Fe trilayers is presented.

scholarly journals LESSONS FROM OXYPNICTIDE THIN FILMS

2012 ◽  
Vol 27 (04) ◽  
pp. 1330001 ◽  
Author(s):  
SILVIA HAINDL ◽  
MARTIN KIDSZUN ◽  
FRANZISKA ONKEN ◽  
ALEXANDER MIETKE ◽  
THOMAS THERSLEFF
Keyword(s):  
Thin Films ◽  
Growth Parameters ◽  
Substrate Surface ◽  
Upper Critical Field ◽  
Epitaxial Thin Films ◽  
Multiband Superconductivity ◽  
Superconducting Transition ◽  
Volatile Elements ◽  
Work Programme

First experiments on the growth of oxypnictide F-doped LaFeAsO thin films indicated an incomplete normal-to-superconducting transition and offered a work programme challenging to overcome possible difficulties in their fabrication. In this regard the possibility of an all in-situ epitaxial growth appeared to be a matter of time and growth parameters. The following review clarifies that F-doped oxypnictide thin films are extremely difficult to grow by in-situ PLD due to the formation of very stable impurity phases such as oxyfluorides (LaOF) and oxides ( La 2 O 3) and the loss of stoichiometry possibly due to incongruent evaporation of the target or re-evaporation of volatile elements at the substrate surface. However, the review also demonstrates that the employed two-step fabrication process for oxypnictide thin films has been successfully applied in the preparation of clean polycrystalline as well as of epitaxial thin films. Fundamental investigations on the upper critical field, its temperature dependence and its anisotropy contributed to an understanding of multiband superconductivity in oxypnictides.

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