Magnetic properties of the HgBa2Ca3Cu4O10+δ superconducting phase

Magnetization data of Al-doped YBCO laser ablated thin films were used to calculate the critical temperature and magnetization of the sample. These were found to be greatly dependent on the dopant concentration. Magnetization curves of samples with different Al concentrations but at the same temperature exhibit similar field dependences with no anomalous behaviour detected. The critical current density J c , extracted from the width of magnetization curve, scaled as J c = J c (0)(1 − T /T c ) n , with n ∼ 2.3. The temperature-dependent pinning force for samples with different Al concentration scaled well as F p = F h0 (T )h p (1 − h) q , where h is the reduced field and p and q are parameters of the order of 0.5 and 2, respectively. This type of scaling is in good agreement with the flux line lattice shear model. F p shows a peak behaviour that scales as a power law of H max (F p ∝ H n max ).

Section: Introductionmentioning

confidence: 99%

“…The samples investigated have included single crystals, thin films, powders, tapes and bulk material. From such measurements valuable information about the behaviour of critical currents [1][2][3], pinning forces [3], irreversibility lines [7,10], flux motion and vortex transitions [1,5] can be extracted.…”

Section: Introductionmentioning

confidence: 99%

Scaling behaviour of Al-doped YBCO laser ablated thin films

Saleh¹,

Hamam²,

Said³

et al. 2000

“…The Hg-1234 phase was first synthesized under high pressure and high temperature and the transition temperature was 126 K at P = 50 kbar [6]. The magnetic properties of the Hg-1234 sample synthesized by this technique are reported in [7]. The temperature dependence of the irreversibility line was found to be similar to that of the other members of the family.…”

Section: Introductionmentioning

confidence: 99%

Effect of cooling rate and strontium doping on the formation of (Hg, Tl)-1234 phase

Abou‐Aly¹,

Ibrahim²,

Korayem³

et al. 2001

Superconductor samples of nominal composition Hg 1−x Tl x Ba 2 Ca 3 Cu 4 O 10+δ (0.3 x 1.0) are prepared at ambient pressure using a closed quartz tube at 850 • C. X-ray powder diffraction for the prepared samples is carried out and the results show that the structure of this system is a tetragonal. The lattice parameters a and c are calculated, and the data indicate that a is not affected by the substitution of Tl 3+ into Hg 2+ , whereas c decreases as the Tl content increases. The superconductivity is investigated using the electrical resistance and ac magnetic susceptibility measurements. All the samples have a superconducting behaviour except when x = 0.3. To improve the superconducting properties of this system, the cooling rate for the sample with x = 0.7 is studied; also the replacement of Ca by Sr for both x = 0.3 and x = 0.5 have been investigated. The excess conductivity for x = 0.3 shows that the dimensionality is changed from two-dimensional in the high-temperature region to three-dimensional in the mean field region.

“…Due to the low growth kinetics at low vapour pressure of mercury, large single crystal growth at normal pressure is still difficult [7,8]. Figure 1 presents the distribution of T c versus number of CuO layers within Hg-based HTS crystal cells produced using various technologies.…”

Section: Introductionmentioning

confidence: 99%

High gas pressure for HTS single crystals and thin layer technology

Morawski

Łada

Paszewin

et al. 1998

The properties of single crystals and thin/thick layers of high- superconductors (HTS, up to 135 K) made under equilibrium conditions of vapour and oxygen are presented. The special high gas pressure apparatus combined with a method of avoiding impurities from the outer volume of the crucible was designed and successfully applied in high pressure experiments. This apparatus was used successfully in experiments with active gases such as oxygen and nitrogen, as well as chlorides, heavy metals, sulphur, fluoride, potassium, sodium and oxides, whch all produce very high partial pressure. As a result we obtained large single crystals of the mercury family of HTS compounds. The obtained single crystals and thin layers reveal a high chemical stability, which suggests their possible future application as superconducting microelectronic devices. The method presented has been successfully applied to obtain other compounds, e.g. (the HgTl-HTS family), YBCO, infinite layer and applied for modern thin layer photovoltaic cells.