Effects of substituting calcium for yttrium on the superconducting properties of YBa2Cu3Oz bulk samples

Nazarova, E.; Zaleski, A.; Zahariev, A.; Stoyanova-Ivanova, Angelina; Zalamova, K.

doi:10.1016/j.physc.2004.01.002

Cited by 18 publications

(5 citation statements)

References 36 publications

(22 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The GBs presenting in supercond uc ting layers of coated conductors behave in many ways like bicrystal GBs [9] and Ca doping was applied for increasing J c of coated conductor s [10]. Improvemen t of grain boundary transpor t in bulk melt -processed [11] and sintered [12] YBCO samples with Ca substitution have been also established. Although the effect is smaller than in thin films there are some indications for improved flux pinning.…”

Section: Introductionmentioning

confidence: 99%

Effects of calcium substitution on the superconducting properties of R1−xCaxBa2Cu3Oz (R=Eu, Gd, Er; 0⩽x⩽0.3) polycrystalline samples

Nazarova

Nenkov

Fuchs

et al. 2006

Physica C: Superconductivity

Self Cite

View full text Add to dashboard Cite

The influence of calcium substitution on the supercond ucting properties of polycrystalline R 1-x Ca x Ba 2 Cu 3 O z (R = Eu, Gd, Er; x=0; 0.2; 0.25 and 0.3) samples has been studied by X-ray powder diffraction, ac susceptibility and dc magnetization measureme nt s. The supercond uc ting parameters such as critical temperat ur e, inter -and intra -granular critical current and flux pinning are found to be strongly depende nt both on Ca content and type of R element. The best combination of these parameter s is found for the system Gd 1-x Ca x Ba 2 Cu 3 O z forming R 1+y Ba 2-y Cu 3 O z clusters. The level of overdoping and the type of intergrain connection, were found to be influenced by the R element and the Ca concentration. Flux pinning in Gd 1-x Ca x Ba 2 Cu 3 O z is connected with the presence of R 1+y Ba 2-y Cu 3 O z clusters. PASC: 74.30.C; 74.60.M

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of calcium substitution on the superconducting properties of R1−xCaxBa2Cu3Oz (R=Eu, Gd, Er; 0⩽x⩽0.3) polycrystalline samples

Nazarova

Nenkov

Fuchs

et al. 2006

Physica C: Superconductivity

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since Ca content changed we must consider the total change in the positions of atoms and also the change in charge. The oxygen content was taken from the relation between Ca content and oxygen content that obtained from figures in the references (Nazarova et al, 2004).…”

Section: ……………………(1)mentioning

confidence: 99%

“…………………………… 2where is Ca content and oxygen content in the compound. Also by using the relation from equation 2 reference (Nazarova et al, 2004). Y substitution by Ca was considered from equation 3 which combined the effect of change of valance , by addition of Ca content.…”

Section: ……………………(1)mentioning

confidence: 99%

Investigating Effect of Ca Content on Electrostatic Potential Energy (EP), Critical Temperature and Structure Parameters on Superconductor

Mustafa¹,

Rostam²

2018

RJS

View full text Add to dashboard Cite

In this paper the effect of Ca content in and the relation between electrostatic potential energy, critical temperature lattice parameters , volume lattice parameter , orthorhombicity, and the hole concentration is investigated by applying the ionic model to calculate the change in the electrostatic potential due to increasing the Ca content in the compound in. It is found that Ca 2+ substitution for Y 3+ leads to increase EP caused by increased ion volume and decrease of charge, this explains changes of superconducting structure parameters such as: lattice parameter ,volume lattice parameter , orthorhombicity. Furthermore decreases with increasing Ca content due to increase of EP which leads to change of the crystal structure and thus decreasing oxygen content and as a result decreasing of Finally considering all above effects the increase of EP will increase the superconducting current.

show abstract

“…Schmehl et al [11] reported that by substituting Ca 2+ at Y 3+ site, the weak link effect of high angle GBs in YBCO multilayer films was significantly reduced and the critical current density was enhanced more than seven times. An improvement of GBs transport in bulk melt-processed [12] and sintered [13] YBCO samples by a Ca substitution has been also established. The intergranular current is important not only by itself, but as an element governing the flux pinning and activation energy for flux creep [14,15].…”

Section: Introductionmentioning

confidence: 96%

Intergranular flux pinning in underdoped and overdoped R1−xCaxBa2Cu3Oz (R=Y, Gd; x=0, 0.2) samples

Nazarova

Zaleski

Nenkov

et al. 2008

Physica C: Superconductivity and its Applications

Self Cite

View full text Add to dashboard Cite

The temperature dependences of AC magnetic susceptibility at different magnetic field amplitudes and frequencies are investigated for underdoped and overdoped R (1-x) Ca x Ba 2 Cu 3 O 7-δ (R=Y; Gd and x=0; 0.2) polycrystalline samples. The activation energy, E a , for thermally assisted flux flow (TAFF) in intergranular region is determined. It was established that a correlation exists between the intergranular critical current and flux pinning activation energy. In underdoped samples the intergranular current shows S-I-S behaviour and the activation energy is small, while in overdoped samples the intergranular current is changed to S-N-S type and the activation energy increases. 2D pancake vortices are characteristic of underdoped samples, while 3D vortex system exists in overdoped samples. In fact we demonstrate that Ca substitution not only increases carrier concentration, but improves intergranular activation energy for TAFF. 1

show abstract

Effects of substituting calcium for yttrium on the superconducting properties of YBa2Cu3Oz bulk samples

Abstract: We report systematic studies of AC magnetic susceptibility and transport properties of

Cited by 18 publications

References 36 publications

Effects of calcium substitution on the superconducting properties of R1−xCaxBa2Cu3Oz (R=Eu, Gd, Er; 0⩽x⩽0.3) polycrystalline samples

Effects of calcium substitution on the superconducting properties of R1−xCaxBa2Cu3Oz (R=Eu, Gd, Er; 0⩽x⩽0.3) polycrystalline samples

Investigating Effect of Ca Content on Electrostatic Potential Energy (EP), Critical Temperature and Structure Parameters on Superconductor

Intergranular flux pinning in underdoped and overdoped R1−xCaxBa2Cu3Oz (R=Y, Gd; x=0, 0.2) samples

Contact Info

Product

Resources

About