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Element Substitution Effect in Transition Metal Oxypnictide Re(O 1- x F x )TAs (Re = rare earth, T = transition metal)
- Source :
- Chinese Physics Letters. 25:2235-2238
- Publication Year :
- 2008
- Publisher :
- IOP Publishing, 2008.
-
Abstract
- Different element substitution effects in transition metal oxypnictide Re(O1-xFx)TAs, with Re = La, Ce, Nd, Eu, Gd, Tm, T = Fe, Ni, Ru, are studied. Similar to the La- or Ce-based systems, we find that the pure NdOFeAs shows a strong resistivity anomaly near 145 K, which is ascribed to the spin-density-wave instability. Electron doping by F increases Tc to about 50 K. While in the case of Gd, Tc is reduced below 10 K. The tetragonal ZrCuSiAs-type structure could not be formed for Eu or Tm substitution in our preparing process. For the Ni-based case, although both pure and F-doped LaONiAs are superconducting, no superconductivity is found when La is replaced by Ce in both the cases, instead a ferromagnetic ordering transition is likely to form at low temperature in the undoped sample. We also synthesize LaO1-xFxRuAs and CeO1-xFxRuAs compounds. The metallic behaviour is observed down to 4K.
Details
- ISSN :
- 17413540 and 0256307X
- Volume :
- 25
- Database :
- OpenAIRE
- Journal :
- Chinese Physics Letters
- Accession number :
- edsair.doi...........83aa1d49959b1141899d41ca7485796d