Pressure Studies of the Unconventional Superconductors CeTIn 5 (T: Co,Ir) |
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Authors: | G. Sparn R. Borth E. Lengyel P.G. Pagliuso J. Sarrao F. Steglich |
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Affiliation: | 1. Max-Planck-Institute for the Chemical Physics of Solids , Dresden , Germany Fax: E-mail: sparn@cpfs.mpg.de;2. Max-Planck-Institute for the Chemical Physics of Solids , Dresden , Germany;3. Los Alamos National Laboratory , Los Alamos , NM , 87545 , U.S.A. |
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Abstract: | In the quest for new superconductor compounds which adopt the superconducting state at increasingly higher transition temperatures T c , a non-phonon mediated coupling between the charge carriers seems to play a key role. In order to enhance our understanding of such unconventional coupling mechanisms, we studied a new family of heavy fermion (HF) superconductors CeTIn 5 (T: transition metal) whose properties point toward the realization of unconventional superconductivity (SC): the specific heat, thermal conductivity and nuclear spin-lattice relaxation rate of CeIrIn 5 and CeCoIn 5 decrease as a power law of temperature instead of exponentially for T < T c . We report on measurements of the heat capacity of CeIrIn 5 and CeCoIn 5 at hydrostatic pressures p h 1.6 GPa. In both compounds, T c increases with increasing pressure, while the mass of the quasi-particles m eff decreases, as indicated by the ratio C / T | T c . As a working hypothesis based on theories of a nearly antiferromagnetic Fermi-liquid (NAFFL), this may be interpreted as the stabilization of the superconducting state by an increase of the characteristic spin fluctuation temperature T_{rm SF} (T_{rm SF}propto k_{rm F}^{2}/m_{rm eff}). |
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Keywords: | Heavy Fermion Superconductivity Heat Capacity Pressure |
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