Abstract
High-T c superconductivity withT c onsets up to 42 K (midpoint: 37 K, zero resistance: 34 K) is observed in X-rays homogeneous single phase La1.8Sr0.2CuO4. The quarternary compounds La2−x Ba x CuO4 and La2−x Sr x CuO4 (0≤x≤0.3 for Ba and 0≤x<1 for Sr, depending on the heating conditions) are mixed-valence oxygen defect oxides, characterized by the presence of Cu2+ and Cu3+ simultaneously. These oxides have a tetragonal symmetry (space group:I 4/mmm) similar to that of K2NiF4. We report the synthesis, characterization, and superconducting properties of various high-temperature superconducting La−Ba−Cu−O and La−Sr−Cu−O compounds. Through the substitution of Sr for Ba in these oxygen defect compounds an increasing superconducting transition temperature onset from 28 K to 35 K for La1.8Sr0.1Ba0.1CuO4 was observed. A positive initial pressure coefficient ofdTc/dp=290 (mK/kbar) has been found for La1.8Sr0.2CuO4 with a magnetic susceptibility change consistent with the 100% diamagnetic expectation value.
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References
Gavaler, J.R.: Appl. Phys. Lett.23, 480 (1973)
Johnston D.C., Prakash, H. Zachariasen, W.H., Viswanathan, R.: Mat. Res. Bull.8, 777 (1973)
Sleight, A.W., Gillson, J.L., Bierstedt, P.E.: Solid State Commun.17, 27 (1975)
Bednorz, J.G., Müller, K.A.: Z. Phys. B — Condensed Matter64, 189 (1986)
Michel, C., Raveau, B.: Rev. Chim. Minéral.21, 407 (1984)
Dietrich, M.: KfK 2098, Dissertation Universität Karlsruhe, Germany (1974)
Dietrich, M., Politis, C.: (to be published)
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Politis, C., Geerk, J., Dietrich, M. et al. Superconductivity at 40 K in La1.8Sr0.2CuO4 . Z. Physik B - Condensed Matter 66, 141–146 (1987). https://doi.org/10.1007/BF01311648
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DOI: https://doi.org/10.1007/BF01311648