Anisotropy of oxygen self-diffusion in YBa2Cu3O7−δ single crystals

Бредихин, С. И.; Емельченко, Г. А.; Shechtman, V.Sh.; Zhokhov, A. A.; Carter, S.; Chater, Richard J.; Kilner, John A.; Steele, B.C.H.

doi:10.1016/0921-4534(91)92173-9

Cited by 61 publications

(20 citation statements)

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“…The cause for such discrepancy is the in-and out-diffusion of oxygen, which strongly depends on the type of surface ͑ab, bc, or ac͒, starting oxygen content, ambient oxygen pressure, temperature, and exposure time. 18,19 In this paper, we present the results of a temperaturedependent Raman study of freshly cleaved ab, ac, and bc surfaces of a twin-free YBa 2 Cu 3 O 6.5 ͑YBCO6.5͒ single crystal with a high degree of ortho-II type ordering. This allowed us with great certainty to identify the proper Raman modes of the ortho-II phase and assign them to definite atomic motions via a close comparison to predictions of lattice dynami-cal calculations, as well as to measure the symmetry and strength of the electronic scattering.…”

Section: Introductionmentioning

confidence: 99%

Raman study of twin-free ortho-IIYBa2Cu3O6.5single crystals

et al. 2008

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The polarized Raman scattering spectra from freshly cleaved ab, ac, and bc surfaces of high quality twin-free YBa 2 Cu 3 O 6.5 ͑ortho-II͒ single crystals ͑T c = 57.5 K and ⌬T = 0.6 K͒ were studied between 80 and 300 K. All 11 A g Raman modes expected for the ortho-II structure as well as some modes of B 2g and B 3g symmetries were identified in close comparison to predictions of lattice dynamical calculations. The electronic scattering from the ab planes is strongly anisotropic and decreases between 200 and 100 K within the temperature range of a previously reported pseudogap opening. The coupling of phonons to Raman active electronic excitations manifested by asymmetric ͑Fano͒ profiles of several modes also decreases within the same range. Among the findings that distinguish the Raman scattering of the ortho-II phase from that of the ortho-I phase is the unusual relationship ͑␣ xx Ϸ −␣ yy ͒ between the elements of the Raman tensor of the apex oxygen A g mode.

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Section: Introductionmentioning

confidence: 99%

Raman study of twin-free ortho-IIYBa2Cu3O6.5single crystals

et al. 2008

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“…We can classify these data according to the following four groups: powders [5,8,11], polycrystalline ceramics [7-9, 14, 16, 23], thin films [4,6,13,15,17,21,35,36] and single crystals [2,3,22].…”

Section: Resultsmentioning

confidence: 99%

“…Sometimes the number of data points is insufficient for determining whether an Arrhenius law is valid over . Arrhenius plot of some tracer or self-diffusion coefficients for pure single crystals [2,3] and thin films [35] published in the literature. These tracer diffusion coefficients D * ab (solid symbols) and D * c (open symbols) were estimated from SIMS studies.…”

Section: Resultsmentioning

confidence: 99%

“…The experimental techniques include secondary ion mass spectroscopy (SIMS) [1][2][3][4], thermogravimetric analysis (TGA) [5][6][7][8][9][10][11][12], electric resistivity measurements [13][14][15][16][17][18][19][20][21][22], internal friction studies [23], electrochemical methods [24,25] and neutron diffraction [26,27]. (In [1-5, 10, 11, 23] the tracer or self-diffusion coefficient, and in the other references the chemical diffusion coefficient has been determined).…”

Section: Introductionmentioning

confidence: 99%

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Fe Deposition or Implantation into Vacuum Arc Deposited Cr Films

Heck¹,

Chayahara²,

Horino³

et al. 2003

Jpn. J. Appl. Phys.

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From isothermal four-point electric resistivity measurements we have determined the chemical diffusion coefficients for the in-and out-diffusion of oxygen in epitaxial c-axis oriented films of YBa 2 Cu 3 O 7−δ in the temperature range 500-650 K. At constant oxygen pressure we have observed the temporal changes in resistivity, following small steps upwards or downwards in temperature. At 600 K for the in-and out-diffusion of oxygen we found about the same diffusion coefficient D ab = 2 × 10 −14 cm 2 s −1 . The temperature dependence of D ab could be well fitted by an Arrhenius law, yielding the same activation energy E A = 1.1 eV for the inand out-diffusion.

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“…͑6͒ will always give a good description of the diffusion. The bulk diffusion of oxygen in YBCO 6ϩx is highly anisotropic and takes place predominately in the ab plane, especially at temperatures below 670 K. 30 However, c-axis-oriented YBCO 6ϩx films consist of various grains whose mosaic boundaries act as short circuits for oxygen diffusion. 31,32 Typical activation energies for bulk and interface diffusion of oxygen in YBCO 6ϩx are about 1 eV.…”

Section: ͑6͒mentioning

confidence: 99%

Desorption of oxygen fromYBa2Cu3
Böck
¹
,
Kürsten
²
,
Brühl
³

et al. 1996
Phys. Rev. B

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Phonons of laser-deposited YBa 2 Cu 3 O 6ϩx films on MgO͑100͒ substrates are investigated in a Raman setup as a function of laser power density. Investigations of YBa 2 Cu 3 O 7 films allow us to study oxygen out-diffusion, where the onset of out-diffusion is indicated by the appearance of disorder-induced modes in the Raman spectra. At a pressure of 5ϫ10 Ϫ6 mbar the temperature threshold of the out-diffusion is (490Ϯ15) K. With increasing oxygen pressure the observed temperature thresholds rise only moderately in contrast to the behavior expected from the p ox -T phase diagram of YBa 2 Cu 3 O 6ϩx . Even at 1 bar oxygen partial pressure outdiffusion is observed and tetragonal sites with xϭ0 develop. These observations can be explained by photonstimulated desorption of oxygen. Investigations of YBa 2 Cu 3 O 6 films allow us to study oxygen in-diffusion. In 1 bar oxygen we observe competing oxygen fluxes due to thermally activated diffusion and photon-stimulated desorption. From these measurements we determine an upper bound of the thermal activation energy of the oxygen in-diffusion into YBa 2

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Anisotropy of oxygen self-diffusion in YBa2Cu3O7−δ single crystals

Cited by 61 publications

References 4 publications

Raman study of twin-free ortho-IIYBa2Cu3O6.5single crystals

Raman study of twin-free ortho-IIYBa2Cu3O6.5single crystals

Fe Deposition or Implantation into Vacuum Arc Deposited Cr Films

Desorption of oxygen fromYBa2Cu3
Böck
¹
,
Kürsten
²
,
Brühl
³

et al. 1996
Phys. Rev. B

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Anisotropy of oxygen self-diffusion in YBa2Cu3O7−δ single crystals

Cited by 61 publications

References 4 publications

Raman study of twin-free ortho-IIYBa2Cu3O6.5single crystals

Raman study of twin-free ortho-IIYBa2Cu3O6.5single crystals

Fe Deposition or Implantation into Vacuum Arc Deposited Cr Films

Desorption of oxygen fromYBa2Cu3Böck1, Kürsten2, Brühl3 et al. 1996Phys. Rev. B

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Desorption of oxygen fromYBa2Cu3
Böck
¹
,
Kürsten
²
,
Brühl
³

et al. 1996
Phys. Rev. B