Akademik Veri Yönetim Sistemi
INTERNATIONAL JOURNAL OF MODERN PHYSICS B, cilt.12, sa.2, ss.143-154, 1998 (SCI-Expanded)
Low field magnetic measurements of a re-entrant system Ni81Mn19 as a function of temperature are shown to exhibit two successive transitions. The ac susceptibility shows strong frequency dependence due to the frustrated spins. The freezing temperature, Ti, shifts to higher temperatures with increasing frequency and decreasing ac field amplitude. Its dependence on frequency is associated with the viscuous relaxation of spins during an ac cycle of the measuring field, which can be attributed to the magnetic relaxation of spin clusters. The results support the theory that re-entrant spin glass state is coexistent with the ferromagnetic domains and that no real phase transition to a spin glass state seems to occur. The interplay of magnetic domain formation and movement with the so-called frustrated spins appears to be responsible for the observed dependences.