Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 26: CE: Heavy Fermions
TT 26.1: Vortrag
Mittwoch, 24. März 2010, 14:00–14:15, H21
Evolution of the Electron Spin Resonance (ESR) in the CeFeAs1−xPxO doping series — •Tobias Förster, Anton Jesche, Cornelius Krellner, Jörg Sichelschmidt, Christoph Geibel, and Frank Steglich — Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden
The CeFeAs1−xPxO compounds are structural homologues of the RTPnO (R: rare earth, T: transition metal, Pn: P or As) high temperature superconductors. The doping series owns a rich magnetic phase diagram driven by chemical pressure: CeFeAsO shows spin density wave (SDW) type order of Fe at TSDW≈140 K and antiferromagnetic order (AFM) of Ce3+ at TN=4 K. By substituting P for As the SDW order disappears and the Ce magnetism initially becomes ferromagnetic (FM). Finally CeFePO is a heavy fermion metal with a large Sommerfeld coefficient and no magnetic order[1,2].
In our contribution we present the results of an ESR study on high quality poly- and single crystalline samples from the CeFeAs1−xPxO doping series, covering the hole doping range. We find no signal, neither from Fe nor from Ce, in the samples with SDW and Ce-AFM. The ESR, which originates from the Ce3+ ions, appears when the SDW order of Fe vanishes and the Ce magnetism becomes FM. This is in agreement with our earlier work on CeRuPO and CeOsPO[3]. We will discuss the temperature and doping dependence of the ESR parameters.
[1] Y. Luo et al., arXiv 0907 2961v1 (2009)
[2] E. Brüning et al., Phys. Rev. Lett. 101, 117206 (2008)
[3] C. Krellner et al., Phys. Rev. Lett. 100, 066401 (2008)