Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena

TT 6.72: Poster

Montag, 23. März 2009, 13:00–16:45, P1A

Pressure tuning of magnetism and superconductivity in CeCu₂Si₂ — •Koji Kaneko^1,2, Oliver Stockert¹, Julia Arndt¹, Astrid Schneidewind^3,4, Hirale S. Jeevan¹, Christoph Geibel¹, and Franck Steglich¹ — ¹Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany — ²ASRC, Japan Atomic Energy Agency, Ibaraki, Japan — ³Institut für Festkörperphysik, TU Dresden, Dresden, Germany — ⁴Neutronenforschungsquelle Heinz-Maier-Leibnitz (FRM-II), TU München, Garching, Germany

In order to get insights on the relationship between magnetism and superconductivity in CeCu₂Si₂, neutron scattering experiments under pressure on A-CeCu₂Si₂ were carried out. An application of a small pressure of ∼5 kbar for A-CeCu₂Si₂ can change the ground state from antiferromagnetic to superconducting through the coexistence phase, which gives the opposite effect to Ge doping. We started from the development of a new pressure cell made of a special aluminum alloy, in order to overcome difficulties of pressure experiments, such as higher background from the cell. This new pressure cell was succeeded to hold the required pressure of more than 3 kbar, which is sufficient to kill antiferromagnetism and enter into the superconducting state. Neutron scattering experiments on PANDA at FRM-II confirm the disappearance of the long-range antiferromagnetic order under pressure, whereas weak magnetic signal still remains at the ordering wave vector. The identical behavior was observed for the S-CeCu₂Si₂ with decreasing temperature[1]. Inelastic neutron scattering experiments are currently in progress.

[1] O. Stockert et al., Physica B 403, 973 (2008).