Single crystal study of the layered heavy fermion compounds Ce2PdIn8, Ce3PdIn11, Ce2PtIn8 and Ce3PtIn11.

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 Ce n T m In3n+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°C. Single crystal x-ray data show that Ce2 TIn8 compounds crystallize in the tetragonal Ho2CoGa8 phase (space group P4/mmm) with lattice parameters a=4.6898(3)Å and c=12.1490(8)Å for Pt-based one (Pd: a=4.6881(4)Å and c=12.2031(8)Å). Ce3 TIn11 compounds adopt Ce3PdIn11 structure with a=4.6874(4)Å and c=16.8422(12)Å for Pt-based one (Pd: a=4.6896Å and c=16.891Å). Specific heat experiments on Ce3PtIn11 and Ce3PdIn11 have revealed that both compounds undergo two successive magnetic transitions at T 1 ~2.2K followed by T N ~2.0K and T 1 ~1.7K and T N ~1.5K, respectively. In addition, both compounds exhibit enhanced Sommerfeld coefficients yielding γ Pt=0.300J/molK2 Ce (γ Pd=0.29J/molK2 Ce), hence qualifying them as heavy fermion materials. [ABSTRACT FROM AUTHOR]