Preparation and characterization of RE doped La2-xSrxCuO4

Breuer, M.; Büchner, B.; Müller, Ralf; Cramm, M.; Maldonado, O.; Freimuth, A.; Roden, B.; Borowski, R.; B, Heymer; Wohlleben, D.

doi:10.1016/0921-4534(93)90191-r

Cited by 36 publications

(20 citation statements)

References 13 publications

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“…Studies on LCO doped with both Sr and Nd [765] find similar results. Even in samples carefully preannealed and then quenched from 1150 o C, there is evidence for Sr inhomogeneity.…”

Section: Miscibility Gapsupporting

confidence: 70%

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

Markiewicz

1997

Journal of Physics and Chemistry of Solids

367

280

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The Van Hove singularity (VHS) provides a paradigm for the study of the role of peaks in the density of states (dos) on electronic properties. More importantly, it appears to play a major role in the physics of the high-Tc superconductors, particularly since recent photoemission studies have found that the VHS is close to the Fermi level in most of the high-Tc cuprates near the composition of optimum Tc. This paper offers a comprehensive survey of the VHS model, describing both theoretical properties and experimental evidence for the picture. Special topics discussed include a survey of the Fermi surfaces of the cuprates and related compounds, and an analysis of the reliability of the slave boson approach to correlation effects. While many properties of the cuprates can be qualitatively understood by a simple rigid-band-filling model, this is inadequate for more quantitative results, since correlation effects tend to pin the Fermi level near the VHS over an extended doping range, and can lead to a nanoscale phase separation. Furthermore, the peaks in the dos lead to competition from other instabilities, both magnetic and structural (related to charge density waves). A novel form of dynamic structural instability, involving dynamic VHS-Jahn-Teller effects has been predicted. Scattered through the literature, there is considerable experimental evidence for both nanoscale phase separation of holes, and for local, possibly dynamic, structural disorder. This review attempts to gather these results into a comprehensive database, to sort the results, and to see how they fit into the Van Hove scenario. Recent experiments on underdoped cuprates are found to provide a strong confirmation that the pseudogap is driven by a splitting of the VHS degeneracy.

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“…Studies on LCO doped with both Sr and Nd [765] find similar results. Even in samples carefully preannealed and then quenched from 1150 o C, there is evidence for Sr inhomogeneity.…”

Section: Miscibility Gapsupporting

confidence: 70%

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

Markiewicz

1997

Journal of Physics and Chemistry of Solids

367

280

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“…The polycrystalline samples of La 2−x−y Eu y Sr x CuO 4 used in this study were prepared by a standard solid state reaction 36 . Three series of samples with the following Sr and Eu concentrations have been investigated: one with fixed Eu content (y = 0.2) and various Sr dopings (0 ≤ x ≤ 0.17), and two others with fixed Sr concentrations (x = 0.017; 0.08) and various Eu dopings (0 ≤ x ≤ 0.2).…”

Section: Methodsmentioning

confidence: 99%

Dzyaloshinsky-Moriya spin canting in the low-temperature tetragonal phase ofLa2−x−yEuySrx
Hücker
¹
,
Kataev
²
,
Pommer
³

et al. 2004
Phys. Rev. B
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The Cu spin magnetism in La2−x−yEuySrxCuO4 (x ≤ 0.17; y ≤ 0.2) has been studied by means of magnetization measurements in fields up to 14 Tesla. Our results clearly show that in the antiferromagnetic phase Dzyaloshinsky-Moriya (DM) superexchange causes Cu spin canting not only in the LTO phase but also in the structural low-temperature phases LTLO and LTT. In La1.8Eu0.2CuO4 the canted DM-moment is about 50% larger than in pure La2CuO4 which we attribute to the larger octahedral tilt angle in the Eu-doped compound. We also find clear evidence that the size of the canted DM-moment does not change significantly at the structural transition at TLT from LTO to LTLO and LTT. The most important change induced by the transition is a significant reduction of the magnetic coupling between the CuO2 planes. As a consequence, the spin-flip transition of the canted Cu spins which is observed in the LTO phase for magnetic field perpendicular to the CuO2 planes disappears in the LTT phase. The shape of the magnetization curves changes from the well known spin-flip type to a weak-ferromagnet type. However, no spontaneous weak ferromagnetism is observed even at very low temperatures, which seems to indicate that the interlayer decoupling in our samples is not perfect. Nonetheless, a small fraction ( 15%) of the DM-moments can be remanently magnetized throughout the entire antiferromagnetically ordered LTT/LTLO phase, i.e. for T < TLT and x < 0.02. It appears that the remanent DM-moment is perpendicular to the CuO2 planes. For magnetic field parallel to the CuO2 planes we find that the critical field of the spin-flop transition decreases in the LTLO phase, which might indicate a competition between different inplane anisotropies. To study the Cu spin magnetism in La2−x−yEuySrxCuO4, a careful analysis of the Van Vleck paramagnetism of the Eu 3+ ions was performed.

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“…Using a standard solid state reaction 9 Within a series of samples with identical x (z) the differences of the Sr ͑Zn͒ content are smaller than ⌬xϳϮ0.001 (⌬zϳϮ0.01). In order to obtain this necessary accuracy of the Sr content, a complete series of samples with different z was prepared from the same mixture of La 2 O 3 and SrCO 3 .…”

mentioning

confidence: 99%

Mobility of holes and suppression of antiferromagnetic order inLa2−xSrx
Hücker
¹
,
Kataev
²
,
Pommer
³

et al. 1999
Phys. Rev. B
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We have measured the static magnetic susceptibility and the resistivity of Zn (0рzр0.25) and Sr (0рx р0.03) doped La 2 CuO 4 . Our data clearly show that Zn impurities lead to an increase of the Néel temperature T N in weakly hole doped compounds. This increase of T N correlates with an increase of the resistivity. The analysis of our data strongly suggests that the hole mobility is the most important source for the strong suppression of antiferromagnetic order in La 2Ϫx Sr x CuO 4 . ͓S0163-1829͑99͒50102-1͔ RAPID COMMUNICATIONS R726PRB 59 M. HÜ CKER et al. RAPID COMMUNICATIONSPRB 59 R727 MOBILITY OF HOLES AND SUPPRESSION OF . . . RAPID COMMUNICATIONS R728PRB 59 M. HÜ CKER et al.

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Preparation and characterization of RE doped La2-xSrxCuO4

Cited by 36 publications

References 13 publications

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

Dzyaloshinsky-Moriya spin canting in the low-temperature tetragonal phase ofLa2−x−yEuySrx
Hücker
¹
,
Kataev
²
,
Pommer
³

et al. 2004
Phys. Rev. B
Self Cite

Mobility of holes and suppression of antiferromagnetic order inLa2−xSrx
Hücker
¹
,
Kataev
²
,
Pommer
³

et al. 1999
Phys. Rev. B
Self Cite

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Preparation and characterization of RE doped La2-xSrxCuO4

Cited by 36 publications

References 13 publications

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

Dzyaloshinsky-Moriya spin canting in the low-temperature tetragonal phase ofLa2−x−yEuySrxHücker1, Kataev2, Pommer3 et al. 2004Phys. Rev. BSelf Cite

Mobility of holes and suppression of antiferromagnetic order inLa2−xSrxHücker1, Kataev2, Pommer3 et al. 1999Phys. Rev. BSelf Cite

Contact Info

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About

Dzyaloshinsky-Moriya spin canting in the low-temperature tetragonal phase ofLa2−x−yEuySrx
Hücker
¹
,
Kataev
²
,
Pommer
³

et al. 2004
Phys. Rev. B
Self Cite

Mobility of holes and suppression of antiferromagnetic order inLa2−xSrx
Hücker
¹
,
Kataev
²
,
Pommer
³

et al. 1999
Phys. Rev. B
Self Cite