Insertion of water into rare earth oxocuprates (Ln)Ba2Cu3O7−δ

Günther, W.; Schöllhorn, R.

doi:10.1016/s0921-4534(96)00546-1

Cited by 28 publications

(13 citation statements)

References 16 publications

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“…Upon heating, this phase is transformed in a highly disordered A phase (not described well enough in Ref. 8 to be shown in Fig. 1) with c = 2.64 nm which quickly transforms at room temperature in the presence of water vapor into a nonsuperconducting B phase with c = 2.72 nm.…”

Section: Introductionmentioning

confidence: 81%

“…The authors of Ref. 8 suggest that this phase has a T c slightly higher than that of the starting material. Upon heating, this phase is transformed in a highly disordered A phase (not described well enough in Ref.…”

Section: Introductionmentioning

confidence: 96%

“…The more recent studies (see Ref. 8 and references therein) done by high-resolution electron microscopy, thermogravimetry and x-ray investigations have shown that the 123 superconductors with x Ͻ 0.9 react with water vapor in a topotactic mechanism. The reaction occurs in two stages in the bulk of the material in the rather narrow temperature range of 75-250°C (for YBa 2 Cu 3 O 6.5 ).…”

Section: Introductionmentioning

confidence: 99%

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Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, and
Dooglav
¹
,
Egorov
²
,
Mukhamedshin
³

et al. 2004
Phys. Rev. B
17
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We present a detailed NQR, nuclear magnetic resonance (NMR), and SR study of the magnetic phase obtained during a topotactic chemical reaction of YBa 2 Cu 3 O 6.5 high-temperature superconductor with lowpressure water vapor. 65Cu-enriched samples have been used for NQR/NMR studies which allows to get a good resolution in the Cu͑1͒ NQR and Cu͑2͒ zero field NMR (ZFNMR) spectra. It is shown that the NQR spectrum of the starting material transforms progressively under insertion of water, and almost completely disappears when about one H 2 O molecule is inserted per unit cell. Similarly, a 65Cu ZFNMR signal characteristic of this water inserted material appears and grows with increasing water content, which indicates that the products of the reaction are nonsuperconducting antiferromagnetic phases in which the copper electronic magnetic moments in the CuO 2 bilayers are ordered. The use of 65 Cu-enriched samples allowed us to reliably resolve three different copper resonances which correspond to different internal magnetic fields. The antiferromagnetic phases are also felt by proton NMR which reveals two sites with static internal fields of 150 and about 15 Gauss, respectively. SR studies performed on a series of samples prepared in the same way as the 65 Cu-enriched ones reveal two muon sites with the same local fields as the proton sites, which vanish at T Ϸ 400 K. This indicates that muons preferentially occupy proton vacancy sites, and that the magnetic phases have similar Néel temperatures as the other bilayer undoped cuprate compounds. An analysis of the internal fields on the different spin probes suggests that they can be all assigned to a single magnetic phase at large water content in which the Cu͑1͒ electron spins order with those of the Cu͑2͒. The detailed evolution of the spectra with the progressive increase of water content is shown to be compatible with a coexistence of phases during the early stages ot the reaction. It appears that even samples packed in paraffin underwent a transformation of a substantial part of the sample after 6 years storage in atmosphere. Samples packed in Stycast epoxy resin heated moderately to a temperature ͑200°C͒ undergo a reaction with epoxy decomposition products which yield the formation of the same final compound. It is clear that such effects should be considered quite seriously and avoided in experiments attempting to resolve tiny effects in these materials, such as those performed in some recent neutron scattering experiments.

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Section: Introductionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, and
Dooglav
¹
,
Egorov
²
,
Mukhamedshin
³

et al. 2004
Phys. Rev. B
17
1
2
0
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“…At x = 0.33 the conductivity is remarkably higher, while at lower temperatures (120-140 K) the effect of magnetic ordering is evident [25]. Probably, the crucial role of itinerant electronic species as hindrance of water solubility manifested here is similar to that in the case of YBaaCu307_6 [8,9]. Thus, we checked this conclusion by studying strongly oxygen-deficient Lat_xCa~MnOa.s4 with fairly low conductivity of pure semiconduction type.…”

Section: (5)mentioning

confidence: 74%

“…YBa_,Cu307 can not dissolve any water vapor at all in spite of possessing two empty oxygen positions per unit cell [ 1,8,9]. This has been only one discrepancy with the acidbase conception.…”

Section: Introductionmentioning

confidence: 97%

Well-known perovskites (cerates, cuprates, manganates): Problems and facts; A review of nontraditional approaches

Baikova

Kompan

Nikulin

et al. 2003

Ionics

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Abstract. Phenomena and processes either new or not studied in-depth occurring in perovskite oxides and in systems which contain these compounds are reported and summarized. The materials under consideration are well-known for specific properties, e.g., cerates of alkaline earths are hightemperature proton conductors, manganates are electrode materials of SOFCs and show the effect of colossal magnetoresistance or YBazCu307 cuprates YBa~Cu307 are "high-temperature" superconductors. The presented nontraditional approach consists of considering physical and chemical phenomena and processes, which do not relate to the indicated main properties of the compounds. For instance, BaCeO3 undoped and slightly doped has partially cerium in the form of Ce +3, which provides the effect of blue luminescence which is controlled by thermochemical treatment; H2YBazCu307 manifests mixed proton-electron conduction at 400-550 K under water vapor of 100-300 Pa; La0.67Cao,33MnO2.84 can dissolve some part of water vapor as this occurs in traditional HTPC. The electrochemical cells Pd I HTPC I hydrocuprate I HTPC I Pd and the more simple one Pd I HTPC I Pd show e.m.f, values near I V under certain conditions after polarization by d.c. currents at 420-520 K under different atmospheres. The system water vapor -membrane of undoped BaCeO3-hydride is described. Defect chemistry equations are used to describe some of the phenomena which are employed for the production and storage of pure hydrogen.

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Hydrogen in perovskites: Mechanism of solubility, chemical state, effect on electron subsystem, phase transformation

Baǐkov¹,

Günther²,

Горелов³

et al. 1998

Ionics

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Abstract. The phenomena of hydrogen/water solubility in YBa2Cu307_ 5 and BaCeO 3 undoped and doped by Y and Nd are considered. New experimental data as well as recently published data have been accumulated to discuss the chemical state of protons, taking into account the fairly strong interaction of the protons with the electron subsystem. Phase transformation of the studied oxides induced by hydrogen/water intercalation were revealed by the investigations of thermal effects, Xray diffraction, Raman spectroscopy, inelastic neutron scattering and nuclear quadrupole resonance.

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Insertion of water into rare earth oxocuprates (Ln)Ba2Cu3O7−δ

Cited by 28 publications

References 16 publications

Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, and
Dooglav
¹
,
Egorov
²
,
Mukhamedshin
³

et al. 2004
Phys. Rev. B
17
1
2
0
View full text Add to dashboard Cite

Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, and
Dooglav
¹
,
Egorov
²
,
Mukhamedshin
³

et al. 2004
Phys. Rev. B
17
1
2
0
View full text Add to dashboard Cite

Well-known perovskites (cerates, cuprates, manganates): Problems and facts; A review of nontraditional approaches

Hydrogen in perovskites: Mechanism of solubility, chemical state, effect on electron subsystem, phase transformation

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Insertion of water into rare earth oxocuprates (Ln)Ba2Cu3O7−δ

Cited by 28 publications

References 16 publications

Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, andDooglav1, Egorov2, Mukhamedshin3 et al. 2004Phys. Rev. B17120View full textAdd to dashboardCite

Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, andDooglav1, Egorov2, Mukhamedshin3 et al. 2004Phys. Rev. B17120View full textAdd to dashboardCite

Well-known perovskites (cerates, cuprates, manganates): Problems and facts; A review of nontraditional approaches

Hydrogen in perovskites: Mechanism of solubility, chemical state, effect on electron subsystem, phase transformation

Contact Info

Product

Resources

About

Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, and
Dooglav
¹
,
Egorov
²
,
Mukhamedshin
³

et al. 2004
Phys. Rev. B
17
1
2
0
View full text Add to dashboard Cite

Antiferromagnetic properties of a water-vapor-insertedYBa2Cu3O6.5compound studied by NMR, NQR, and
Dooglav
¹
,
Egorov
²
,
Mukhamedshin
³

et al. 2004
Phys. Rev. B
17
1
2
0
View full text Add to dashboard Cite