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AM: Magnetismus

AM 9: Postersitzung Fürstenberghaus

AM 9.12: Poster

Tuesday, March 18, 1997, 09:30–12:30, F"u

µ SR  ON THE NOVEL HEAVY-FERMION SYSTEM Nd_2−yCe_yCuO₄     — •M. Hillberg, W. Wagener, M.A.C. de Melo, H.-H. Klau"s, W. Kopmann, F.J. Litterst, P. Adelmann, and G. Czjzek —   
^∗ Institut für Metallphysik und Nukleare Festkörperphysik
TU Braunschweig Mendelssohnstraße 3, 38106 Braunschweig
^† Forschungszentrum Karlsruhe, Institut für Nukleare Festkörperphysik
The magnetic correlations in Nd_2−yCe_yCuO₄  have been studied by zero and longitudinal field µ SR . Nd_1.8Ce_0.2CuO₄  reveals a saturation of the muon relaxation rate below 0.5 K. Even down to 70 mK LF spectra evidence spin fluctuations in the dynamic regime with a rate of ∼ 10⁹ s⁻¹ excluding long range magnetic order or spin glass freezing. The average Nd moment is estimated to be ≈ 0.2 µ_B, i. e., strongly reduced from the value determined for the ground state Kramers doublet of Nd₂CuO₄ . Extending former µ SR  measurements on Nd₂CuO₄ , a gradual enhancement of the internal field has been detected below 10 K which is accompanied by an increase of the relaxation rate. These results are attributed to a development of ordered Nd moments.