Spatial inhomogeneity in RFeAs(O,F)(R=Pr,Nd) as revealed by studies of the rare earth crystal field excitations

Journal Article · Sat Jan 01 00:00:00 EST 2011 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.83.212505· OSTI ID:1017314

Goremychkin, E. A. ^[1]; Osborn, R. ^[1]; Wang, Cuihuan ^[2]; Lumsden, Mark D ^[2]; McGuire, Michael A ^[2]; Safa-Sefat, Athena ^[2]; Sales, Brian C ^[2]; Mandrus, David ^[2]; Ronnow, H. M. ^[3]; Su, Y. ^[4]; Christianson, Andrew D ^[2]

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1. Argonne National Laboratory (ANL)
2. ORNL
3. Lab for Quantum Magnetism, Switzerland
4. Forschungszentrum Julich, Julich, Germany

We report inelastic neutron-scattering measurements of crystal-field transitions in PrFeAsO, PrFeAsO{sub 0.87}F{sub 0.13}, and NdFeAsO{sub 0.85}F{sub 0.15}. Doping with fluorine produces additional crystal-field excitations, providing evidence that there are two distinct charge environments around the rare-earth ions, with probabilities that are consistent with a random distribution of dopants on the oxygen sites. The 4f electrons of the Pr{sup 3+} and Nd{sup 3+} ions have nonmagnetic and magnetic ground states, respectively, indicating that the enhancement of T{sub c} compared to LaFeAsO{sub 1-x}F{sub x} is not due to rare-earth magnetism.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1017314
• Journal Information: Physical Review B, Vol. 83, Issue 21; ISSN 1098--0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTAL FIELD
DISTRIBUTION
ELECTRONS
FLUORINE
GROUND STATES
MAGNETISM
OXYGEN
RARE EARTHS