Size effects in microparticle high temperature superconducting ceramics YBa2Cu3O7-δ and Bi2CaSr2Cu2O8+y

Multani, M.S.; Guptasarma, P.; Palkar, V. R.; Ayyub, Pushan; Gurjar, A.

doi:10.1016/0375-9601(89)90333-2

Cited by 22 publications

(7 citation statements)

References 15 publications

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“…For the most part, we restrict our review to conventional (BCS-like) superconducting metals, simply because there is little hope of comprehending size-induced perturbations in the high-T C systems unless the corresponding bulk ground state properties are relatively well understood. Also, soon after the discovery of the two prototypic high-T C oxides, YBa 2 Cu 3 O 7 − x and Bi 2 CaSr 2 Cu 2 O 8 , it was shown that in quasi-free (unstrained) nanoparticles of these systems, size effects appear to be dominated by structural effects [39] at rather large sizes (50-100 nm). In this review, we present some of the generally accepted models that are used for understanding the variation of superconducting properties with particle sizes in BCS-like metallic superconductors, and also discuss some of the recently observed phenomena in single nanoparticles.…”

Section: Elementmentioning

confidence: 99%

“…Nanocrystalline elemental (Nb, Pb, etc) superconducting thin films have been grown by sputtering [16,38] and by evaporation or chemical deposition through nanoporous templates [35]. Structurally complex high temperature oxide superconductors, on the other hand, have been grown in nanoparticle form (loose powder or compacted pellets) by chemical techniques such as co-precipitation [39], rapid dehydration [40] and microemulsion-based reactions [41]. All such samples allow the measurement of ensembleaveraged superconducting properties through bulk techniques such as transport, magnetization and fabrication of large area tunnel junctions [6,7,10,16,35,38,[42][43][44].…”

Section: Introductionmentioning

confidence: 99%

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A review of finite size effects in quasi-zero dimensional superconductors

Bose

Ayyub

2014

Rep. Prog. Phys.

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Quantum confinement and surface effects (SEs) dramatically modify most solid state phenomena as one approaches the nanometer scale, and superconductivity is no exception. Though we may expect significant modifications from bulk superconducting properties when the system dimensions become smaller than the characteristic length scales for bulk superconductors-such as the coherence length or the penetration depth-it is now established that there is a third length scale which ultimately determines the critical size at which Cooper pairing is destroyed. In quasi-zero-dimensional (0D) superconductors (e.g. nanocrystalline materials, isolated or embedded nanoparticles), one may define a critical particle diameter below which the mean energy level spacing arising from quantum confinement becomes equal to the bulk superconducting energy gap. The so-called Anderson criterion provides a remarkably accurate estimate of the limiting size for the destabilization of superconductivity in nanosystems. This review of size effects in quasi-0D superconductors is organized as follows. A general summary of size effects in nanostructured superconductors (section 1) is followed by a brief overview of their synthesis (section 2) and characterization using a variety of techniques (section 3). Section 4 reviews the size-evolution of important superconducting parameters-the transition temperature, critical fields and critical current-as the Anderson limit is approached from above. We then discuss the effect of thermodynamic fluctuations (section 5), which become significant in confined systems. Improvements in fabrication methods and the increasing feasibility of addressing individual nanoparticles using scanning probe techniques have lately opened up new directions in the study of nanoscale superconductivity. Section 6 reviews both experimental and theoretical aspects of the recently discovered phenomena of 'parity effect' and 'shell effect' that lead to a strong, non-monotonic size dependence of the superconducting energy gap and associated properties. Finally, we discuss in section 7 the properties of ordered heterostructures (bilayers and multilayers of alternating superconducting and normal phases) and disordered heterostructures (nanocomposites consisting of superconducting and normal phases), which are primarily controlled by the proximity effect.

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Section: Elementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A review of finite size effects in quasi-zero dimensional superconductors

Bose

Ayyub

2014

Rep. Prog. Phys.

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“…Moreover, for low Z elements, such as oxygen, determination of exact number is difficult as it is. However, the purpose of carrying out electron microprobe analysis was to find out relative changes in oxygen stoichiometry with size since in many other oxide systems oxygen deficiency with reduction in size has been observed [7,8]. Magnetic transition temperature (T M ) was determined using differential thermal analyzer (DTA).…”

Section: ____________________________________________________________mentioning

confidence: 99%

Properties of magnetite nanoparticles synthesized through a novel chemical route

et al. 2004

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We have developed a simple precipitation route to synthesize magnetite (Fe 3 O 4 ) nanoparticles with controlled size without any requirement of calcination step at high temperatures. The study of these nano-particles indicates an enhancement in saturation magnetization with reduction in size down to ~10 nm beyond which the magnetization reduces. The latter is attributed to surface effects becoming predominant as surface to core volume ratio increases. From the view -point of applications, 10 nm size of magnetite particles seems to be the optimum.

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“…In spite of their being aliovalent, no resemblance to the aliovalent (and hence easily able to perturb the local environment) Ti and Nb behaviour is seen (Figure 59b). The above results have to be seen in the light of the fact that an 80 K phase is known to persist inspite of considerable changes in stoichmiometry (Multani et al, 1989~).…”

Section: Symmetry-breaking In Bicasro + Ymentioning

confidence: 90%

Limiting long-range-ordered solids to finite sizes in condensed-matter physics

et al. 1990

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We have examined some of the consequences of finite size effects in solids which exhibit cooperative behaviour. These are materials with long-range interactions based on ferromagnetism, ferroelectricity, and superconductivity. Limiting the range of interaction is achieved by creating nanocrystals, nanodomains, disorder, high-concentration solid solutions and submicron microstructure in sintered compacts. The attempt is to elucidate underlying principles essential at a microscopic level for each of the three phenomena. Not much work has been reported in this area earlier and most of the results are from our own studies. Some of the work is reported for the first time. The experimental techniques used are Mossbauer, Raman and infrared spectroscopies, high-temperature x-ray diffraction, electron energy loss spectroscopy, dielectric and piezoelectric response, ferromagnetic resonance and spinwave dispersion, 4-probe resistivity, DC & AC magnetic susceptibilities and differential scanning calorimetry.

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Size effects in microparticle high temperature superconducting ceramics YBa2Cu3O7-δ and Bi2CaSr2Cu2O8+y

Cited by 22 publications

References 15 publications

A review of finite size effects in quasi-zero dimensional superconductors

A review of finite size effects in quasi-zero dimensional superconductors

Properties of magnetite nanoparticles synthesized through a novel chemical route

Limiting long-range-ordered solids to finite sizes in condensed-matter physics

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