Physical properties of the ${\mathrm{Ce}}_{2}M\mathrm{Al}{}_7{\mathrm{Ge}}_4$ heavy-fermion compounds $(M=\text{Co},\text{Ir},\text{Ni},\text{Pd})$

Journal Article · Mon May 23 04:00:00 UTC 2016 · Physical Review B

DOI: https://doi.org/10.1103/PhysRevB.93.205141 · OSTI ID:1334137

Ghimire, N. J. ^[1]; Cary, S. K. ^[2]; Eley, S. ^[1]; Wakeham, N. A. ^[1]; Rosa, P. F. S. ^[1]; Albrecht-Schmitt, T. ^[2]; Lee, Y. ^[3]; Janoschek, M. ^[1]; Brown, C. M. ^[4]; Civale, L. ^[1]; Thompson, J. D. ^[1]; Ronning, F. ^[1]; Bauer, E. D. ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry and Biochemistry
3. Center for Artificial Low Dimensional Electronic Systems, Pohang (Korea). Inst. for Basic Science
4. Center for Neutron Research, Gaithersburg, MD (United States). National Inst. of Standards and Technology

Here, we report the synthesis, crystal structure, and characterization by means of single-crystal x-ray diffraction, neutron powder diffraction, and magnetic, thermal, and transport measurements of the new heavy-fermion compounds Ce₂MAl₇Ge₄ (M=Co,Ir,Ni,Pd). These compounds crystallize in a noncentrosymmetric tetragonal space group P$$\bar{4}$$2₁m, consisting of layers of square nets of Ce atoms separated by Ge-Al and M-Al-Ge blocks. Ce₂CoAl₇Ge₄,Ce₂IrAl₇Ge₄, and Ce₂NiAl₇Ge₄ order magnetically below TM=1.8, 1.6, and 0.8 K, respectively. There is no evidence of magnetic ordering in Ce₂PdAl₇Ge₄ down to 0.4 K. Furthermore, the small amount of entropy released in the magnetic state of Ce₂MAl₇Ge₄ (M = Co, Ir, Ni) and the reduced specific heat jump at T_M suggest a strong Kondo interaction in these materials. Ce₂PdAl₇Ge₄ shows non-Fermi liquid behavior, possibly due to the presence of a nearby quantum critical point.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC52-06NA25396; SC0010677
• OSTI ID: 1334137
• Report Number(s): LA-UR--15-27485
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 20 Vol. 93; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English