Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 4: Schwere Fermionen, Kondo-Systeme

TT 4.6: Vortrag

Montag, 24. März 2003, 16:00–16:15, HSZ03

Evolution of Superconductivity and Magnetism in the Heavy-Fermion System CeRh_1−x,Ir_xIn₅ with Pressure and Doping — •M. Nicklas^1,2, H. A. Borges¹, V. A. Sidorov¹, N. O. Moreno¹, P. G. Pagliuso¹, Z. Fisk¹, J. L. Sarrao¹, and J. D. Thompson¹ — ¹Los Alamos National Laboratory, Los Alamos, NM 87545, USA — ²Max-Planck-Inst. for the Chem. Phys. of Solids, Dresden, Germany

Alloys within the CeRh_1−xIr_xIn₅ series of heavy-fermion materials provide an interesting interplay of antiferromagnetism and unconventional superconductivity. At atmospheric pressure, antiferromagnetism exists for 0≤ x≤0.65 and superconductivity is present for 0.35≤ x≤1.0. In addition to microscopic coexistence of antiferromagnetism and superconductivity for 0.35≤ x≤0.65, the Ir-rich alloys also show two anomalous features: their resistivity goes to zero at temperatures much higher than the bulk superconducting temperature and there is a peculiar absence of superconductivity near x≈0.9. Pressure studies on single crystals in this series show that at 1.75 GPa the entire phase field is superconducting except for a narrow range of Ir concentrations 0.75≤ x≤0.9 and the bulk superconducting temperature approaches the temperature where the resistivity goes to zero. We discuss the pressure evolution of superconductivity and magnetism in the context of multiple quantum critical points and the possible existence of a spin pseudogap in Rh-rich alloys.