Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 8: Superconductivity: Fe-based Superconductors - 122 Part 1

TT 8.1: Talk

Monday, March 26, 2012, 15:00–15:15, H 2053

Elastic anomalies in Ba(Fe_1−xCo_x)₂As₂ — •Christoph Meingast¹, Anna Böhmer^1,2, Frederic Hardy¹, Philipp Burger^1,2, Peter Adelmann¹, Doris Ernst¹, Rainer Fromknecht¹, Peter Schweiss¹, Rolf Heid¹, and Thomas Wolf¹ — ¹Karlsruhe Institute of Technology, Institute for Solid State Physics, 76021 Karlsruhe, Germany — ²Karlsruhe Institute of Technology, Fakultät für Physik, 76128 Karlsruhe, Germany

The elastic properties of Ba(Fe_1−xCo_x)₂As₂ single crystals are studied using a three-point-bending arrangement in a capacitance dilatometer. In this novel setup, a constant pressure is applied and the elastic response is determined as a function of temperature. In the undoped compound we find a very large softening of the elastic response at the structural/magnetic transitions near 140 K. The high resolution of this setup allows us to distinguish the behavior at both transitions. The large softening for undoped crystals weakens with doping and in the overdoped crystals only the very small softening as usually seen in superconductors at T_c is observed. We discuss our results in light of recent ultrasound measurements [1,2].
R. M. Fernandes et al., Phys. Rev. Lett. 105, 157003 (2010).
Y. Yoshizawa et al., arXiv: 1111.0366