Effect of pressure and quenching on superconductive<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn><mml:mo>+</mml:mo><mml:mi mathvariant="normal">δ<

Zhou, Jianshi; Chen, H.; Goodenough, John B

doi:10.1103/physrevb.50.4168

Cited by 32 publications

(16 citation statements)

References 28 publications

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“…1͒ was closely comparable with those reported, for example, in Ref. 4. The superconducting transition was centered at 34 K and the resistivity below 5 K was lower than 1 ⍀ cm, indicating a good connectivity between the grains.…”

Section: Methodssupporting

confidence: 91%

“…1,3͒ or introducing interstitial O. 4 It should be noted that in the new phase the octahedra are also distorted. 5,6 The LTO phase tends to transform into LTT or Pccn at a lower temperature T d2 in La 2Ϫx M x CuO 4ϩ␦ (M ϭBa, Sr͒, but the formation of stable LTT domains seems to require a mismatch between the ionic radii in the La sublattice.…”

Section: Introductionmentioning

confidence: 99%

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Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuO
Cordero
¹
,
Grandini
²
,
Cannelli
³

et al. 1998
Phys. Rev. B
36
5
24
0
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The anelastic spectrum ͑dynamic Young's modulus and elastic energy absorption͒ of La 2 CuO 4ϩ␦ has been measured between 1 and 700 K with 0Ͻ␦Ͻ0.02. The spectrum of stoichiometric La 2 CuO 4 in the lowtemperature orthorhombic ͑LTO͒ phase is dominated by two intense relaxation processes which cause softenings of 16% around 150 K and 9% below 30 K at f ϳ1 kHz. The relaxation at 150 K is attributed to the presence of a fraction of the CuO 6 octahedra which are able to change their tilted configuration by thermal activation between orientations which are nearly energetically equivalent, possibly within the twin boundaries. The relaxation below 30 K is governed by tunneling, and involves a considerable fraction of the lattice atoms. It is proposed that the double-well potentials for the low-temperature relaxation are created by the tendency of the LTO phase to form low-temperature tetragonal ͑LTT͒ domains, which however are not stabilized like when La is partially substituted with Ba. On doping with excess O, the relaxation rates of these processes are initially enhanced by hole doping, while their intensities are depressed by lattice disorder; an explanation of this behavior is provided. Excess O also causes two additional relaxation processes. The one appearing at lower values of ␦ is attributed to the hopping of single interstitial O 2Ϫ ions, with a hopping rate equal to Ϫ1 ϭ2ϫ10Ϫ14 exp(Ϫ5600/T) s. The second process is slower and can be due to O pairs or other complexes containing excess O. ͓S0163-1829͑98͒03210-X͔

show abstract

Section: Methodssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuO
Cordero
¹
,
Grandini
²
,
Cannelli
³

et al. 1998
Phys. Rev. B
36
5
24
0
View full text Add to dashboard Cite

show abstract

“…It is possibly because of the presence of oxygen vacancies that reside in the CuO 2 planes or orthorhombic-tetragonal phase fluctuation in LSCO. However, similar results are observed in interstitially doped La 2 CuO 4+δ where the excess oxygen is located relatively far from CuO 2 planes [25]. Also, no anomalous behavior is observed in the temperature dependence of TEP near the orthorhombic-tetragonal transition temperature.…”

Section: Resultssupporting

confidence: 68%

Two Pseudogap Behavior in La_2-xSr_xCuO₄: Thermoelectric Power at High Temperature

Kim

et al. 2004

Journal of Superconductivity

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Thermoelectric power (TEP) of high-T C superconductors has been investigated in a wide range of temperature (T C < T < 700 K) for La 2−x Sr x CuO 4 . TEP of La 2−x Sr x CuO 4 shows different temperature dependences in three temperature regions. In the low-temperature region, a positive broad TEP peak is observed near T p , which shifts to lower temperature upon doping. As temperature increases, TEP decreases linearly at intermediate temperature.In the high-temperature region, TEP deviates from the linear temperature dependence at a certain temperature, T h showing a saturation behavior. As the doping concentration increases, the characteristic temperatures, T C , T p , and T h , show systematic changes. In comparison with pseudogap temperature estimated from other experiments, the large pseudogap behavior in TEP at high temperature has been discussed and distinguished from the small pseudogap observed at lower temperature. A possibility of bound pairs formation in the normal state opening the pseudogap at high temperature is discussed briefly. The coexistence of bound pairs and the normal independent carriers for T C < T < T h could be the origin of the intrinsic inhomogeneity.

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“…In the case of the copper-oxide superconductors, which are also at a cross-over from localized to itinerant electronic behavior, we have argued that pseudo J-T deformations in the copper-oxide superconductors are dynamic and stabilize non-adiabatic, multi-copper dielectric polarons that condense into mobile stripes consisting of alternating hole-rich and hole-poor ribbons within the superconductive CuO 2 planes (67)(68)(69)(70)(71)(72)(73).…”

Section: At Temperatures T > T C the Paramagnetic Susceptibility Ofmentioning

confidence: 99%

Jahn-Teller Phenomena in Solids

Goodenough

1998

Annu. Rev. Mater. Sci.

Self Cite

259

217

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Jahn-Teller phenomena encountered in oxides are reviewed briefly. High-spin Mn(III) in an octahedral site illustrates an ion with twofold orbitally degenerate σ -bonding orbitals having a quenched orbital angular momentum; octahedral V(III) and high-spin Co(II), as well as tetrahedral high-spin Ni(II), are examples of ions with threefold orbitally degenerate π-bonding orbitals that retain orbital angular momentum. Cooperative local deformations that are static give rise, below a transition temperature T t , to a lowering of the lattice symmetry, anisotropic interactions, and the possibility of a ferromagnetism that is oriented in opposition to a magnetic field applied on cooling through the transition. Dynamic local deformations can influence the physical properties of a solid in a variety of ways. Of special interest is the influence of dynamic deformations at a cross-over from localized to itinerant electronic behavior in a mixed-valent system.

show abstract

Effect of pressure and quenching on superconductiveLa2CuO4+δ<

Cited by 32 publications

References 28 publications

Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuO
Cordero
¹
,
Grandini
²
,
Cannelli
³

et al. 1998
Phys. Rev. B
36
5
24
0
View full text Add to dashboard Cite

Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuO
Cordero
¹
,
Grandini
²
,
Cannelli
³

et al. 1998
Phys. Rev. B
36
5
24
0
View full text Add to dashboard Cite

Two Pseudogap Behavior in La_2-xSr_xCuO₄: Thermoelectric Power at High Temperature

Jahn-Teller Phenomena in Solids

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Effect of pressure and quenching on superconductiveLa2CuO4+δ<

Cited by 32 publications

References 28 publications

Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuOCordero1, Grandini2, Cannelli3 et al. 1998Phys. Rev. B365240View full textAdd to dashboardCite

Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuOCordero1, Grandini2, Cannelli3 et al. 1998Phys. Rev. B365240View full textAdd to dashboardCite

Two Pseudogap Behavior in La2-xSrxCuO4: Thermoelectric Power at High Temperature

Jahn-Teller Phenomena in Solids

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Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuO
Cordero
¹
,
Grandini
²
,
Cannelli
³

et al. 1998
Phys. Rev. B
36
5
24
0
View full text Add to dashboard Cite

Thermally activated dynamics of the tilts of the CuO6octahedra, hopping of interstitial O, and possible instability towards the LTT phase in La2CuO
Cordero
¹
,
Grandini
²
,
Cannelli
³

et al. 1998
Phys. Rev. B
36
5
24
0
View full text Add to dashboard Cite

Two Pseudogap Behavior in La_2-xSr_xCuO₄: Thermoelectric Power at High Temperature