Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 26: CE: Heavy Fermions

TT 26.3: Vortrag

Mittwoch, 24. März 2010, 14:30–14:45, H21

Ferromagnetic 4f Correlations in the Oxypnictides CeFe_1−xRu_xPO: A ³¹P NMR Study — •Eva Maria Brüning, Cornelius Krellner, Michael Baenitz, Christoph Geibel, and Frank Steglich — Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany

CeTPO (T = Ru, Os, Fe), homologues of the new oxypnictide superconductors, show dissimilar types of ground states. CeRuPO is a rare example of a ferromagnetically ordered Kondo-lattice system (T_C=15 K), whereas CeOsPO shows antiferromagnetic order and weak Kondo interaction (T_N= 3.5 K) [1]. CeFePO is a paramagnetic heavy fermion system in the vicinity of ferromagnetic order [2]. Therefore it became very interesting to investigate the solid solution series CeFe_1−xRu_xPO (x = 0.1, 0.2) to trace the crossover from a ferromagnetically correlated heavy fermion system (x = 0) to a ferromagnetically ordered metal (x = 1) through a possible quantum critical point. We applied the microscopic NMR method on polycrystals and performed a temperature and field dependent ³¹P NMR study. The investigations of the Knight shift ³¹K(T) and spin-lattice-relaxation rate ³¹(1/T₁) of the new systems CeFe_1−xRu_xPO (x = 0, x = 0.1, x= 0.2) are presented.

[1] C. Krellner, N. S. Kini, E. M. Brüning, K. Koch, H. Rosner, M. Nicklas, M. Baenitz, C. Geibel Phys. Rev. B, 76; 104418 (2007)

[2] E. M. Brüning, C. Krellner, M. Baenitz, A. Jesche, C. Geibel, F. Steglich, Phys. Rev. Lett, 101; 117206 (2008)