Dresden 2011 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 15: SC: Fabrication and Characterization
TT 15.1: Talk
Monday, March 14, 2011, 16:30–16:45, HSZ 301
Enhanced two-dimensional behavior of metastable T′-La2CuO4, the parent compound of electron-doped cuprate superconductors — •Alexander Buckow1, Roland Hord2, Hubertus Luetkens3, Gwendolyne Pascua3, Kathrin Hofmann2, Jose Kurian1, Vladimir Pomjakushin4, Andreas Suter3, Barbara Albert2, and Lambert Alff1 — 1Institute of Materials Science, TU Darmstadt — 2Eduard-Zintl-Institute, TU Darmstadt — 3Laboratory for Muon Spin Spectroscopy, PSI — 4Laboratory for Neutron Scattering, PSI
We synthesized crystalline bulk samples of lanthanum cuprate in the metastable T′ phase using cesium hydroxide flux. Its crystal structure was determined as space group I4/mmm, no. 139, a = 401.02 pm, c = 1252.66 pm. Muon spin rotation reveals a gradual slowing down of magnetic order below TN2 = 115 K, in sharp contrast to La2CuO4 in the T structure where TN1 ≈ TN2 ≈ 300 K. Our result shows that the strikingly different magnetic behavior of the two parent compounds has its origin in the two crystal structure modifications. In addition, we find that T′-La2CuO4 has strongly reduced magnetic interactions compared to the other T′ materials Nd2CuO4 and Pr2CuO4, where Nd3+ and Pr3+ are magnetic ions in contrast to the nonmagnetic La3+.
R. Hord, H. Luetkens, G. Pascua, A. Buckow, K. Hofmann, Y. Krockenberger, J. Kurian, H. Maeter, H.-H. Klauss, V. Pomjakushin,
A. Suter, B. Albert, and L. Alff, Phys. Rev. B 82, 180508(R) (2010).