Interstitial oxygen mobility in superconducting samples of Bi2Sr2CaCu2O8+y

Gimenez, J. M. A.; Grandini, Carlos Roberto; Santos, Dayse Iara dos

doi:10.1088/0953-2048/19/8/021

Cited by 5 publications

(4 citation statements)

References 19 publications

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“…The peak P3 and P4 were observed by Gimenez et al [2,11]. In BSCCO superconductors, a structural transformation occurs from the superconducting orthorhombic phase to the monoclinic non-superconducting phase (O-M phase transformation).…”

Section: Resultsmentioning

confidence: 81%

“…The monoclinic phase transformation was associated with the easy diffusion of oxygen atoms out of the crystal at high temperature (350-400 o C) and high vacuum (1.5 x 10 -7 mbar), causing local distortions. Due to the local distortions, which is caused by the O-M phase transition, the peak P4 was associated with these structural phase transformations [2]. In a BSCCO lattice, additional oxygen atoms (y > 0) are found in the BiO layers in interstitial positions between two Bi atoms.…”

Section: Resultsmentioning

confidence: 99%

“…Since materials with superconducting properties in high-temperatures (type II) were discovered, many studies have been accomplished with the objective of understanding the mechanisms that allow such behavior [1]. In the case of the superconducting oxides, it is believed that the oxygen atoms dissolved interstitially have fundamental role in the superconductivity of these materials, due to their facility to move into the lattice, in addition to contributing to the hole creation in the of CuO 2 planes [2].…”

Section: Introductionmentioning

confidence: 99%

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Oxygen Interstitial Dynamics in Bi2Sr2CaCu2O8+δ Oxides Measured by Mechanical Spectroscopy

Grandini

Ruiz

Silva

et al. 2008

MSF

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Many researchers became interested in the discovery of Bi2Sr2CaCu2O8+δ oxides with critical temperature of around 80 K. It is known that the critical temperature is related to the CuO2 planes of the material. For this reason, the study of the interstitial oxygen in these oxides is of great relevance. The samples were prepared by means of conventional solid state reactions, through the stoichiometric mixture of precursory powders. After the sinterization, the samples were submitted to measurements of density, electrical resistivity, x-ray diffraction, scanning electron microscopy and energy dispersion spectroscopy, with the objective of performing their characterization. The measurements of mechanical spectroscopy were performed by a torsion pendulum. The results show three relaxation processes in the temperature range of 200 and 700 K, with activation energy of approximately 0.9 eV, which has been attributed to the dynamics of the interstitial oxygen present in the material.

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Section: Resultsmentioning

confidence: 81%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Oxygen Interstitial Dynamics in Bi2Sr2CaCu2O8+δ Oxides Measured by Mechanical Spectroscopy

Grandini

Ruiz

Silva

et al. 2008

MSF

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“…At least three maxima appear at 200, 350, and 450 K. It can be observed that the intensity of these peaks increases as the interstitial oxygen content increases. These three processes are obviously due to the interstitial oxygen [13].…”

Section: Resultsmentioning

confidence: 99%

Oxygen Diffusion in Superconducting Oxides

Grandini

Gimenez

Silva

et al. 2008

DDF

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Since the discovery of high-temperature superconductivity of cuprate oxides, it has been clear that it is strongly affected by the oxygen content, which is also a crucial factor to determine other physical properties of high Tc superconductors. Non-stoichiometric (interstitial) oxygen strongly influences the physical properties of various superconducting oxides, in particular by creating conducting holes. It is now ascertained that the amount of holes injected depends not only on the content of interstitial oxygen, but also on its ordering. Rearrangement of the oxygen ordering may occur even below room temperature due to the unusual high mobility of these atoms. This way, mechanical spectroscopy is one of the most adequate techniques for the study of the mobility (diffusion) of oxygen atoms. This technique allows the determination of the jump frequency of an atomic species precisely, regardless of the model or the different possible types of jumps. In order to evaluate the mobility and the effect of oxygen content on these oxides, ceramic samples we prepared and submitted to several oxygen removal cycles alternately with mechanical relaxation measurements. As for SBCO, it was assumed that the peak was due to O(1)-O(5) jumps of oxygen atoms at the chain terminals or in chain fragments in the orthorhombic phase. In the case of BSCCO, the results showed complex anelastic relaxation structures, which were attributed to interstitial oxygen atom jumps between two adjacent CuO planes.

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