Low-Field Microwave Absorption in High-TC Superconducting Oxides

1987 ◽  
Vol 99 ◽  
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.

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

1991 ◽  
Vol 05 (09) ◽  
pp. 667-674 ◽  
Author(s):  
K. SUGAWARA ◽  
T. SUGIMOTO ◽  
K. YASUIKE ◽  
D.J. BAAR ◽  
Y. SHIOHARA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Microwave Absorption ◽  
Applied Field ◽  
Film Plane ◽  
Experimental Results ◽  
High Tc Superconductors ◽  
High Tc ◽  
Low Field ◽  
Absorption Studies

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.

scholarly journals Comparison of Pr-doped Ca 122 and Ca 112 Pnictides by Low-field Microwave Absorption Spectroscopy

2014 ◽  
Vol 1684 ◽  
Author(s):  
Austin R. Howard ◽  
Jonathan D. Yuen ◽  
Bing Lv ◽  
Myron Salamon ◽  
Ching-Wu Chu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Microwave Absorption ◽  
Absorption Spectroscopy ◽  
Superconducting State ◽  
Superconducting Phase ◽  
Interfacial Phase ◽  
Low Field ◽  
Low Magnetic Field ◽  
Anisotropic Magnetization

ABSTRACTPraseodymium doped CaFe2As2 (122 structure) and CaFeAs2 (112 structure) are characterized by modulated Low Magnetic Field Microwave Absorption (LFMA) spectroscopy. In both (Pr,Ca)122 and (Pr,Ca)112 structures, a strong hysteretic LFMA is found, with a TcH of ∼30 K and ∼26 K, respectively. However, in (Pr,Ca)122, measurements also show an unusual Narrow Peak (NP) LFMA signal appearing at higher temperatures, above the lower TcH superconducting state until a TcNP of 49 K. We associate this NP LFMA with interfacial superconductivity, which has been found previously by highly anisotropic magnetization measurements. Furthermore, the absence of NP in (Pr,Ca)112 correlates with the absence of an interfacial phase. These results give useful information about the microwave signature of interfacial superconductivity present in the (Pr,Ca)122 system, and may form a roadmap towards a stabilized high temperature superconducting phase in pnictides.

Modulated microwave absorption in single crystal Bi–Sr–Ca–Cu–O

1992 ◽  
Vol 7 (4) ◽  
pp. 837-843
Author(s):  
R.S. Rubins ◽  
Z. Trybula ◽  
S. Waplak ◽  
John E. Drumheller ◽  
Donglu Shi ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Modulation Amplitude ◽  
Broad Line ◽  
Low Field ◽  
A Value ◽  
Flux Trapping ◽  
Line Absorption ◽  
The Relationship ◽  
Maximum Field ◽  
Absorption Measurements

Modulated microwave absorption measurements at 9.3 GHz were made on the low field absorption observed in the superconducting phase of Bi–Sr–Ca–Cu–O. The line intensity observed with a low modulation amplitude of 50 mOe showed a maximum between 70 K and 80 K and dropped to zero near 95 K. With a modulation amplitude of 10 Oe, an additional broad line absorption was observed above 88 K, peaking in intensity near 95 K, and disappearing above 100 K. Hysteresis, associated with flux trapping, occurred when the maximum field Hmax in a sweep cycle exceeded a critical value H*(T), which varied from about 7 Oe at 59 K to 1 Oe at 82 K. For Hmax > H*, the hysteresis splitting at first varied linearly with (Hmax – H*), later saturating at a value δHmax(T). Above 70 K, the relationship δHmax = b(T0 – T) was obeyed with T0 = 92.3 K and b· = −0.3 Oe/K for H perpendicular and b· = −0.23 Oe/K for H parallel to the c-axis.

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

1992 ◽  
Vol 06 (05) ◽  
pp. 265-272 ◽  
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).

ANOMALOUS BEHAVIORS OF NON-RESONANT MICROWAVE ABSORPTIONS OF SUPERCONDUCTORS

2000 ◽  
Vol 14 (16) ◽  
pp. 1633-1650
Author(s):  
K. SUGAWARA ◽  
N. ARAI ◽  
A. KOUZUKI ◽  
S. ICHIMURA ◽  
H. NAOI ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Applied Magnetic Field ◽  
Microwave Power ◽  
Superconducting Thin Films ◽  
Modulation Amplitude ◽  
Directional Effect ◽  
System A ◽  
Powder Samples ◽  
Preliminary Study

The non-resonant microwave absorption (NRMA) measurements have been intensively performed for superconducting thin films of YBa 2 Cu 3 O y fabricated on MgO (100) substrates and powder samples of LaSrCuO systems. In order to complement the study, we also review the NRMA of BiSrCaCuO system. A particular attention has been paid to the following phenomena: (i) phases, (ii) effect of current, (iii) directional effect of applied magnetic field, (iv) hysteresis, (v) microwave power absorbed as a function of magnetic field, (vi) linewidth in the vicinity of T c , and (vii) modulation amplitude effect. A preliminary study on ( La 0.98 Dy 0.02)1.85 Sr 0.15 CuO 4 was also reported.

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

1988 ◽  
Vol 133 (6) ◽  
pp. 339-341 ◽  
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

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

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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