Local structure and site occupancy of Cd and Hg substitutions in CeTIn5 (T=Co, Rh, Ir)
- Los Alamos National Laboratory
- LBNL
- UC, IRVINE
- LSU
- UC-IRVINE
The CeTIn{sub 5} superconductors (T = Co, Rh, or Ir) have generated great interest due to their relatively high transition temperatures, non-Fermi liquid behavior, and their proximity to antiferromagnetic order and quantum critical points. In contrast to small changes with the T-species, electron doping in CeT(In{sub 1-x}M{sub x}){sub 5} with M = Sn and hole doping with Cd or Hg have a dramatic effect on the electronic properties at very low concentrations. The present work reports local structure measurements using the extended x-ray absorption fine-structure (EXAFS) technique that address the substituent atom distribution as a function of T, M, and x, in the vicinity of the superconducting phase. Together with previous measurements for M = Sn, the proportion of the M atom residing on the In(1) site, f{sub 1n(1)}, increases in the order M = Cd, Sn, and Hg, ranging from about 40% to 70%, showing a strong preference for each of these substituents to occupy the In(1) site (random occupation = 20%). In addition, f{sub In(1)} ranges from 70% to 100% for M = Hg in the order T = Co, Rh, and Ir. These fractions track the changes in the atomic radii of the various species, and help explain the sharp dependence of T{sub c} on substituting into the In site. However, it is difficult to reconcile the small concentrations of M with the dramatic changes in the ground state in the hole-doped materials with only an impurity scattering model. These results therefore indicate that while such substitutions have interesting local atomic structures with important electronic and magnetic consequences, other local changes in the electronic and magnetic structure are equally important in determining the bulk properties of these materials.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 962304
- Report Number(s):
- LA-UR-09-01316; LA-UR-09-1316; TRN: US200919%%67
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
Similar Records
X-ray absorption near-edge studies of substitution for Cu in YBa sub 2 (Cu sub 1 minus x M x ) sub 3 O sub 7 minus. delta. ( M =Fe, Co, Ni, and Zn)
A moving target: responding to magnetic and structural disorder in lanthanide- and actinide-based superconductors