Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: Correlated Electrons: Heavy Fermions

TT 6.3: Vortrag

Montag, 25. Februar 2008, 10:00–10:15, EB 202

Investigation of the magnetic and the superconducting states of CeCu₂(Si_1−xGe_x) using single crystals — •Hirale S Jeevan¹, Takeshi Nakanishi¹, Julia Arndt¹, Enrico Faulhaber², Oliver Stockert¹, Micha Deppe¹, Tomasz Cichorek¹, Frank Steglich¹, and Christoph Geibel¹ — ¹Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Gemany — ²TU Dresden, IAPD, D-01062 Dresden, Germany

The discovery of superconductivity in CeCu₂Si₂ in 1979 opened the field of unconventional superconductivity in strongly correlated systems. Later on, another unconventional phase, the A-phase, of magnetic character was found to compete with the superconducting phase in CeCu₂Si₂. Recent neutron experiment confirms that the A-phase is nothing but the long range antiferromagnetic order, spin density wave type due to nesting of heavy Fermi surface. And in pure CeCu₂Si₂ it was shown that the long range magnetic phase and superconducting phase compete each other. Here we investigate the magnetic and the superconducting states in a series of Ge substituted single crystals CeCu₂(Si_1−xGe_x) with x = 0.02 and 0.1. Ge substitution has two effect, stabilises the magnetic phase due to expansion of the lattice, but it also induce disorder effect. Based on the earlier results on polycrystalline samples, we expect the possible co-existing of both long range magnetic phase and superconducting phase in some Ge concentration range. We shell analyse and discuss the single crystal growth, physical properties and neutron scattering measurements of these Ge substituted single crystals.