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AM: Magnetismus

AM 18: Postersitzung Fürstenberghaus

AM 18.25: Poster

Mittwoch, 19. März 1997, 14:30–17:30, F"u

SPIN DYNAMICS IN THE REENTRANT SPIN GLASS
(Fe_0.65Ni_0.35)_1−xMn_x    — •H.-H. Klau"s, M. Hillberg, W. Wagener, M.A.C. de Melo, W. Kopmann, F.J. Litterst, M. Fricke, J. Hesse, and E. Schreier —   
^∗ Institut für Metallphysik und Nukleare Festkörperphysik
TU Braunschweig Mendelssohnstraße 3, 38106 Braunschweig
^‡ Hahn-Meitner-Institut, Glienicker Str. 100, 14109 Berlin
^† Physik Department E 1

The spin dynamics in the reentrant spin glass (Fe_0.65Ni_0.35)_1−xMn_x  has been studied by zero, longitudinal and transverse field µSR. In the ferromagnetic reentrant and pure spin glass regimes (x ≤ 0.175) zero field experiments reveal a streched exponential muon relaxation with a universal behaviour of the dynamic exponent β above the spin glass transition. There are no qualitative differences between the ferromagnetic and paramagnetic phases. In transversal field µSR  experiments the divergence of the relaxation rate close to the spin glass transition is suppressed for Manganese doping up to x = 0.113 but enhanced for slightly higher doping (x ≥ 0.12). We understand this behaviour as a crossover from an itinerant to a more localized state of the 3d electron system. This is also supported by the fact that in the highly doped regime with dominant antiferromagnetic interactions the muon relaxation rate diverges above the antiferromagnetic transition temperature.