MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS I—LOW-FIELD MICROWAVE ABSORPTION IN A BiSrCaCuO THIN FILM DEPOSITED BY MOCVD

Non-resonant microwave absorption as a function of temperature and magnetic field has been studied in a Bi-Sr-Ca-Cu-O film prepared by MOCVD. A maximum in the absorption as a function of temperature was observed at approximately 60 K. An average Josephson loop diameter of about 0.9~1.5 microns was inferred from the experimental results. The absorption was found to depend on the angle of the film plane relative to the applied field.

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MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS VI—NON-RESONANT MICROWAVE ABSORPTION IN ULTRA-THIN Bi-Sr-Ca-Cu-O FILMS—

Modern Physics Letters B ◽

10.1142/s0217984992000351 ◽

1992 ◽

Vol 06 (05) ◽

pp. 265-272 ◽

Cited By ~ 4

Author(s):

K. SUGAWARA ◽

T. SUGIMOTO ◽

D.J. BAAR ◽

Y. SHIOHARA ◽

S. TANAKA

Keyword(s):

Magnetic Field ◽

Microwave Absorption ◽

Signal Intensity ◽

Critical Magnetic Field ◽

High Tc Superconductors ◽

Temperature Relation ◽

High Tc ◽

Absorption Studies ◽

Increasing Temperature ◽

Mgo Substrate

Non-resonant microwave absorption (NRMA) studies have been done for Bi-Sr-Ca-Cu-O (BSCCO) films with thicknesses of 30 Å and 15 Å fabricated on MgO substrate by MOCVD. For the latter two kinds of samples have been fabricated: BSCCO/MgO and BiOx/BSCCO/MgO . NRMA signals have been detected up to about 70–75 K for all the samples. The lower critical magnetic field H c1 * of the 30 Å film was severely increased by the application of a magnetic field of several kGauss, whereas it is almost unaffected in the case of 15 Å films. H c1 * increases but the signal intensity decreases with increasing temperature for all the 30 Å and 15 Å samples. The temperature dependence of the intensity is quite different from that of thicker films (100 Å and 350 Å), in which the intensity vs. temperature relation has a peak (or peaks) at particular temperature(s).

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MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS VII — ESR OF DPPH COATED ON A THIN BiSrCaCuO FILM FABRICATED ON MgO(100) SUBSTRATE

Modern Physics Letters B ◽

10.1142/s0217984992000764 ◽

1992 ◽

Vol 06 (11) ◽

pp. 675-682

Author(s):

K. SUGAWARA ◽

T. SUGIMOTO ◽

Y. SHIOHARA ◽

S. TANAKA

Keyword(s):

Magnetic Field ◽

Critical Current Density ◽

Temperature Dependence ◽

Microwave Absorption ◽

Current Density ◽

Applied Magnetic Field ◽

High Tc Superconductors ◽

High Tc ◽

Absorption Studies ◽

Mpmg Method

ESR of DPPH coated on a Bi-Sr-Ca-Cu-O (BSCCO) film (350 Å thick) fabricated on MgO(100) substrate by MOCVD was studied. Temperature dependence of the ESR peak-to-peak linewidth, ΔH pp , and the effect of applied magnetic field on ΔH pp have been studied below about 100 K. The results were compared with those of ESR of DPPH coated on ceramic Y-Ba-Cu-O samples (powder and bulk) made by the MPMG method. The DPPH ESR for the BSCCO film revealed that ΔH pp was independent of applied magnetic field up to about 9 kG. In addition, no similarity between the temperature dependence of the excess ESR linewidth of the DPPH and that of critical current density was found for the BSCCO film. These results for the BSCCO film are different from those for the MPMG YBCO samples.

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MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS V-ANOMALOUS BEHAVIOR OF LOW MAGNETIC FIELD MICROWAVE ABSORPTION IN AN ULTRA-THIN Bi-Sr-Ca-Cu-O FILM

Modern Physics Letters B ◽

10.1142/s0217984991002380 ◽

1991 ◽

Vol 05 (30) ◽

pp. 1981-1987 ◽

Cited By ~ 3

Author(s):

K. SUGAWARA ◽

T. SUGIMOTO ◽

D.J. BAAR ◽

Y. SHIOHARA ◽

S. TANAKA

Keyword(s):

Magnetic Field ◽

Temperature Dependence ◽

Microwave Absorption ◽

Anomalous Behavior ◽

High Tc Superconductors ◽

High Tc ◽

Absorption Studies ◽

Signal Changes ◽

Low Magnetic Field ◽

Mgo Substrate

Non-resonant microwave absorption (NRMA) studies have been done on a 100 Å thick Bi-Sr-Ca-Cu-O film fabricated on MgO substrate by MOCVD. Temperature dependence of NRMA intensity reveals that the intensity becomes maximum at around 30 K, 40 K and 55 K, and minimum at around 35 K and 50 K. The sign (or phase) of the signal changes by passing through these intensity minimum temperatures. Furthermore, the linewidths of the NRMA signals anomalously increase in the vicinity of these temperatures.

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Temperature dependence of the low field microwave absorption of high Tc superconductors

Physics Letters A ◽

10.1016/0375-9601(88)90457-4 ◽

1988 ◽

Vol 133 (6) ◽

pp. 339-341 ◽

Cited By ~ 7

Author(s):

A.R. Harutyunyan ◽

L.S. Grigoryan ◽

M. Baran ◽

S. Piechota

Keyword(s):

Temperature Dependence ◽

Microwave Absorption ◽

High Tc Superconductors ◽

High Tc ◽

Low Field

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MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS VIII — ESR OF DPPH COATED ON BiSrCaCuO FILMS FABRICATED ON MgO (100) SUBSTRATES

Modern Physics Letters B ◽

10.1142/s0217984992001733 ◽

1992 ◽

Vol 06 (14) ◽

pp. 879-889

Author(s):

K. SUGAWARA ◽

S. TANAKA

Keyword(s):

Magnetic Field ◽

Film Thickness ◽

Temperature Dependence ◽

Applied Magnetic Field ◽

Zero Field ◽

Magnetic Field Effects ◽

High Tc Superconductors ◽

Thick Sample ◽

High Tc ◽

Absorption Studies

ESR of DPPH coated on Bi - Sr - Ca - Cu - O films fabricated on MgO (100) substrates by MOCVD have been studied for samples with different thicknesses, 1000 Å and 100 Å. Temperature dependence of the ESR peak-to-peak linewidth, ΔH pp , revealed that ΔH pp , increases with film thickness. The excess ESR linewidth, δ (ΔH pp ) was also analyzed in terms of (1-t)α, with t=T/T c , giving for example α=4±1 for the 1000 Å thick sample. The ESR lineshapes were distorted by rotating the samples in applied magnetic fields. Severe distortion was found for the 1000 Å sample below about 30 K, but the distortion almost disappears at temperatures above 30 K. The applied magnetic field effects were also examined in both field-cooled and zero-field-cooled cases.

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On the origin of low field microwave absorption in the high Tc superconductors

Physica C Superconductivity ◽

10.1016/0921-4534(89)90836-8 ◽

1989 ◽

Vol 162-164 ◽

pp. 1589-1590

Author(s):

M.D. Sastry ◽

R.M. Kadam ◽

A.G.I. Dalvi ◽

G.M. Phatak ◽

R.M. Iyer

Keyword(s):

Microwave Absorption ◽

High Tc Superconductors ◽

High Tc ◽

Low Field

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Paramagnetic species and magnetic surface structures in high-TC superconductors as revealed by electron spin resonance and low-field nonresonant microwave absorption.

Hyomen Kagaku ◽

10.1380/jsssj.9.521 ◽

1988 ◽

Vol 9 (7) ◽

pp. 521-529 ◽

Cited By ~ 2

Author(s):

Atsushi MAEDA ◽

Haruo KURODA ◽

Takeji TAKUI

Keyword(s):

Electron Spin Resonance ◽

Microwave Absorption ◽

Electron Spin ◽

Magnetic Surface ◽

Surface Structures ◽

Paramagnetic Species ◽

High Tc Superconductors ◽

High Tc ◽

Low Field ◽

Spin Resonance

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Low-field microwave absorption in high-Tc superconductors based on olygo- and polyphthalocyanines

Physics Letters A ◽

10.1016/0375-9601(92)90963-m ◽

1992 ◽

Vol 162 (1) ◽

pp. 69-78 ◽

Cited By ~ 4

Author(s):

L.S. Lyubchenko ◽

S.V. Stepanov ◽

M.L. Lyubchenko ◽

A.I. Sherle ◽

V.R. Epshtein

Keyword(s):

Microwave Absorption ◽

High Tc Superconductors ◽

High Tc ◽

Low Field

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Low-Field Microwave Absorption in High-TC Superconducting Oxides

MRS Proceedings ◽

10.1557/proc-99-455 ◽

1987 ◽

Vol 99 ◽

Cited By ~ 1

Author(s):

B. L. Ramakrishna ◽

E. W. Ong ◽

Z. Iqbal

Keyword(s):

Magnetic Field ◽

Particle Size ◽

Composite Material ◽

Microwave Absorption ◽

Superconducting State ◽

Microwave Power ◽

Modulation Amplitude ◽

High Tc ◽

Low Field ◽

Superconducting Oxides

ABSTRACTLow-field non-resonant microwave absorption in an EPR spectrometer has been observed in the superconducting state of different samples of the new high-T oxides, YBa2Cu3O7-δ and La1.8Sr0.2CuO4. It has been attributed to flux slippage occurring at the Josephson junctions existing in the granular composite material. The dependence on particle size, temperature, microwave power, DC modulation amplitude and magnetic field has been studied.

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Enhancing Superconducting Parameters by Array of External Magnetic Dots

MRS Proceedings ◽

10.1557/proc-1180-cc05-09 ◽

2009 ◽

Vol 1180 ◽

Author(s):

Wei Jiang Yeh ◽

Bo Cheng

Keyword(s):

Magnetic Field ◽

Thin Film ◽

Thin Films ◽

Pinning Force ◽

High Tc Superconductors ◽

High Tc ◽

Current Value ◽

Magnetic Dots ◽

The Magnetic Field ◽

Superconducting Parameters

AbstractEnhancing the pinning force in high-Tc superconductors can be achieved by externally introduced periodic magnetic dots. We use a novel nano-technique to deposit periodic sub-micon Ni dots on YBa2Cu3O7 thin films. The current versus voltage characteristics of an YBa2Cu3O7 thin film strip with uniform Ni dots are measured at various temperatures and magnetic fields. They are compared with the current versus voltage characteristics of a bare YBa2Cu3O7 thin film strip without magnetic dots. It is found the critical current value of the strip with Ni dots reduces with a much slower pace as the magnetic field strength increases in comparison with the value of the bare sample.

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