scholarly journals Width of the zero-field superconducting resistive transition in the vicinity of the localization threshold

JETP Letters ◽  
2001 ◽  
Vol 73 (3) ◽  
pp. 131-134 ◽  
Author(s):  
V. F. Gantmakher ◽  
M. V. Golubkov
1998 ◽  
Vol 12 (29n31) ◽  
pp. 3259-3263
Author(s):  
Ben De Mayo

The zero-field intersample variability of the superconducting transition temperature was measured for two commercially supplied Ag-clad Bi2Sr2Ca2Cu3O x, (Bi(2223)) 37 filament tapes, one 103 m and the second 193 m long. The resistivity of six 30 cm long pieces of each tape was measured with increasing and decreasing temperature. Hysteresis and time-dependent effects were observed. For the 103 m tape, upon cooling, the resistivity deviates from the conventional behavior at (114.3.3.2) K and complete superconductivity is achieved at (105.1.3.9) K. With increasing temperature deviation from superconductivity starts at (112.5.4.6) K and superconductivity is completely gone at (121.8.3.1) K. The corresponding temperatures for the 193 m tape are (113.4.4.9), (108.6.3.6), (108.9.7.4) and (118.1.7.4) K. For one sample of the 193 m tape, the corresponding temperatures are (107.9.3.1), (102.5.5.9), (100.8.4.3) and (112.0.3.3) K. The anomalously broad foot structure in the zero field resistive transition previously seen by Zhao et al. (Ref. 1) in single crystals of Bi2Sr2CaCu2O x, (Bi(2212)) was observed here, too.


Author(s):  
Z. L. Wang ◽  
C. L. Briant ◽  
J. DeLuca ◽  
A. Goyal ◽  
D. M. Kroeger ◽  
...  

Recent studies have shown that spray-pyrolyzed films of the Tl-1223 compound (TlxBa2Ca2Cu3Oy, with 0.7 < × < 0.95) on polycrystalline yttrium stabilized zirconia substrates can be prepared which have critical current density Jc near 105 A/cm2 at 77 K, in zero field. The films are polycrystalline, have excellent c-axis alignment, and show little evidence of weak-link behavior. Transmission electron microscopy (TEM) studies have shown that most grain boundaries have small misorientation angles. It has been found that the films have a nigh degree of local texture indicative of colonies of similarly oriented grains. It is believed that inter-colony conduction is enhanced by a percolative network of small angle boundaries at colony interfaces. It has also been found that Jc is increased by a factor of 4 - 5 after the films were annealed at 600 °C in oxygen. This study is thus carried out to determine the effect on grain boundary chemistry of the heat treatment.


2021 ◽  
Author(s):  
Júlia Mayans ◽  
Albert Escuer

A possible relation between the value of the axial Zero Field Splitting and the occurrence of field-induced slow magnetic relaxation has been established for a new gadolinium(iii) compound.


1979 ◽  
Vol 40 (C1) ◽  
pp. C1-335-C1-337 ◽  
Author(s):  
J. Carmeliet ◽  
J. C. Dehaes ◽  
W. Singer

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1373
Author(s):  
Fadis F. Murzakhanov ◽  
Boris V. Yavkin ◽  
Georgiy V. Mamin ◽  
Sergei B. Orlinskii ◽  
Ivan E. Mumdzhi ◽  
...  

Optically addressable high-spin states (S ≥ 1) of defects in semiconductors are the basis for the development of solid-state quantum technologies. Recently, one such defect has been found in hexagonal boron nitride (hBN) and identified as a negatively charged boron vacancy (VB−). To explore and utilize the properties of this defect, one needs to design a robust way for its creation in an hBN crystal. We investigate the possibility of creating VB− centers in an hBN single crystal by means of irradiation with a high-energy (E = 2 MeV) electron flux. Optical excitation of the irradiated sample induces fluorescence in the near-infrared range together with the electron spin resonance (ESR) spectrum of the triplet centers with a zero-field splitting value of D = 3.6 GHz, manifesting an optically induced population inversion of the ground state spin sublevels. These observations are the signatures of the VB− centers and demonstrate that electron irradiation can be reliably used to create these centers in hBN. Exploration of the VB− spin resonance line shape allowed us to establish the source of the line broadening, which occurs due to the slight deviation in orientation of the two-dimensional B-N atomic plains being exactly parallel relative to each other. The results of the analysis of the broadening mechanism can be used for the crystalline quality control of the 2D materials, using the VB− spin embedded in the hBN as a probe.


2021 ◽  
Author(s):  
Plinio Cantero-López ◽  
Yoan Hidalgo-Rosa ◽  
Zoraida Sandoval-Olivares ◽  
Julián Santoyo-Flores ◽  
Pablo Mella ◽  
...  

Rhenium tricarbonyl complexes are one of the most important classes of coordination compounds in inorganic chemistry. Exploring their luminescent excited states, lowest singlet (S1), and the lowest triplet (T1), is...


Sign in / Sign up

Export Citation Format

Share Document