Single crystal study of the layered heavy fermion compounds Ce2PdIn8, Ce3PdIn11, Ce2PtIn8 and Ce3PtIn11
Abstrakt
We report on single crystal growth and crystallographic parameters results of Ce2PdIn8, Ce3PdIn11, Ce2PtIn8 and Ce3PtIn11. The Pt-systems Ce2PtIn8 and Ce3PtIn11 are synthesized for the first time.
All these compounds are member of CenTmIn3n+2m (n=1, 2, ..; m=1, 2,.. and T= transition metal) to which the extensively studied heavy fermion superconductor CeCoIn5 belongs. Single crystals have been grown by an In self-flux method.
Differential scanning calorimetry studies were used to derive optimal growth conditions. Evidently, the maximum growth conditions for these materials should not exceed 750 degrees C.
Single crystal x-ray data show that Ce2TIn8 compounds crystallize in the tetragonal Ho2CoGa8 phase (space group P4/mmm) with lattice parameters a=4.6898(3) angstrom and c=12.1490(8) angstrom for Pt-based one (Pd: a=4.6881(4) angstrom and c=12.2031(8) angstrom). Ce3TIn11 compounds adopt Ce3PdIn11 structure with a=4.6874(4) angstrom and c=16.8422(12) angstrom for Pt-based one (Pd: a=4.6896 angstrom and c=16.891 angstrom).
Specific heat experiments on Ce3PtIn11 and Ce3PdIn11 have revealed that both compounds undergo two successive magnetic transitions at T-1 similar to 2.2 K followed by T-N similar to 2.0 K and T-1 similar to 1.7 K and T-N similar to 1.5 K, respectively. In addition, both compounds exhibit enhanced Sommerfeld coefficients yielding gamma(Pt)=0.300 J/mol K-2 Ce (gamma(Pd)=0.29 J/mol K-2 Ce), hence qualifying them as heavy fermion materials.