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TT: Fachverband Tiefe Temperaturen

TT 14: Superconductivity: Non-Cuprate Non-Ferropnictide Superconductors

TT 14.5: Vortrag

Dienstag, 24. März 2009, 11:00–11:15, HSZ 105

Doping effect on Pauli limited superconductor CeCoIn₅ — •Yoshi Tokiwa — I. Physik. Institut, Georg-August Universitat Gottingen, Friedrich-Hund Platz 1, 37077 Göttingen

We present a study on the proposed FFLO state in the strongly Pauli limited superconductor CeCoIn₅ by measuring specific heat of slightly Hg- and Sn-doped compounds, CeCo(In_1−xHg_x)₅ and CeCo(In_1−xSn_x)₅ with x from 0.01 to 0.08%. The high-field low-temperature (HFLT) superconducting (SC) phase exhibits an extreme sensitiveness to the doping, i. e., HFLT phase being suppressed by ∼0.05% of Hg-doping or ∼0.08% of Sn-doping. Our results suggest a possible relation between the characteristic length scale of HFLT phase and SC coherence length. Interestingly, the HFLT transition temperature T_HFLT increases with increasing Hg-doping concentration, while it decreases as Sn is doped. A plot of T_HFLT vs T_c at high fields with doping concentration as an implicit parameter shows a scaling of the two, T_HFLT∝ T_c. We conclude that these results imply SC origin of the HFLT state rather than antiferromagnetism.

This work has been done by the collaboration with R. Movshovich, F. Ronning, E. D. Bauer, J. D. Thompson, P. Papin, A. D. Bianchi, J. F. Rauscher, S. F. Kauzlarich and Z. Fisk.