Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 31: Superconductivity: Fe-based Superconductors – 122 and 111

TT 31.5: Talk

Tuesday, March 17, 2015, 10:45–11:00, H 2053

Phase transitions and phase separation in undoped and Rh doped CaFe₂As₂ — Vladimir Gnezdilov^1,2, •Peter Lemmens¹, Yurii Pachkevich³, Tetiana Shevtsova³, Masataka Danura⁴, Masakazu Kobayashi⁴, Tasuku Mizukami⁴, Kazutaka Kudo⁴, and Minoru Nohara⁴ — ¹IPKM, TU-BS, Braunschweig — ²ILTPE NAS, Ukraine — ³DonFTI, Donetsk, Ukraine — ⁴Department of Physics, Okayama, Japan

Iron-pnictides Ca(Fe1-xRhx)₂As₂ (x = 0, 0.035 and 0.19) were studied across the tetragonal-orthorhombic and tetragonal collapsed tetragonal phase transitions using Raman spectroscopy. Effects of phase separation were observed in the high-temperature phase for the first time. An orbital order scenario at low temperatures for the Rh doped samples which requires a symmetry lowering down to P4/mnc or I422 without atomic displacements relative to the parent I4/mmm symmetry is discussed.

Work supported by RTG-DFG 1953/1, Metrology for Complex Nanosystems.