Dresden 2003 – wissenschaftliches Programm
MA 6.13: Vortrag
Montag, 24. März 2003, 18:15–18:30, HSZ/04
Aging and Relaxation Behavior of Superferromagnetic Domain State — •Xi Chen1, O. Sichelschmidt1, O. Petracic1, Ch. Binek1, W. Kleemann1, S Cardoso2, and P. P. Freitas2 — 1Laboratorium für Angewandte Physik, Gerhard-Mercator-Universität Duisburg — 2INESC, Rua Alves Redol 9-1, 1000 Lisbon, Portugal
The magnetic relaxation of the superferromagnetic discontinuous magnetic multilayer [Co80Fe20(1.4 nm)/Al2O3(3 nm)]10 is investigated by SQUID magnetometry. After cooling the sample in a field from 400 K to different measurement temperatures, the decay of the thermoremanent magnetic moment mTRM is measured. Surprisingly, an intermediate increase of mTRM is observed, hence, two competing relaxation behaviors have to be assumed. One is the relaxation of the superferromagnetic domains, and the other one is the post-alignment of the frozen thermal disorder of the superspins inside the domains. In addition, aging and memory effects are found revealing the non-equilibrium behavior of the superferromagnet.