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TT: Fachverband Tiefe Temperaturen

TT 30: Superconductivity - Poster Session

TT 30.35: Poster

Montag, 31. März 2014, 15:00–19:00, P2

A light scattering study of detwinned BaFe₂As₂ — •Andreas Baum¹, Andreas Walter¹, Bernhard Muschler¹, Florian Kretzschmar¹, Jiun-Haw Chu^2,3, James G. Analytis^2,3, Ian R. Fisher^2,3, and Rudi Hackl¹ — ¹Walther-Meissner-Institut, 85748 Garching, Germany — ²SIMES, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA — ³GLAM and Department of Applied Physics, Stanford, University, Stanford, CA 94305, USA

The magneto-structural phase transition of BaFe₂As₂ is studied by Raman spectroscopy with a focus on lattice dynamics. Using uniaxial pressure to detwin the sample allows us to resolve anisotropic features as well as a separation of the structural and magnetic phase transitions.

The As A_1g phonon shows a resonance at high energies. With the polarizations aligned along either the antiferromagnetically or the ferromagnetically ordered direction the resonance profile is distinctly different.

The splitting of the E_g phonon at 135   cm⁻¹ into two modes having B_2g and B_3g symmetry can be attributed to the transition into the magnetically ordered state rather than the structural transition.