Book of abstracts of workshop "Modern problems of Soft Matter theory" 27-31 Aug. 2000, Lviv.
I.Mryglod
Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, UA-79011 Lviv, Ukraine,
mryglod@icmp.lviv.ua
S. Dubyk and Yu. Rudavskii
State University ``Lvivska Politekhnika'', UA-79013 Lviv, Ukraine
Investigation of magnetic liquids is the great interest due to interaction between liquid and magnetic subsystem. Recent report on experiments with liquid metals and alloys gave impact for our investigation with static and dynamical properties of Heisenberg model ferrofluid in external magnetic field. Static properties of magnetic liquids have been theoretically studied within the functional approach, spin-relaxation theory, on the base of phenomenological equations of motion and in various numerical compute simulations. The papers [1,2] in according of collective modes formalism the hydrodynamic equations for collective excitations and time correlation functions in the hydrodynamic limit were considered. After choosing four dynamical variables which correspond to the conserved parameters analyzed a structure of all time correlation functions. The dynamic structure factor in this case will include the term related with the influence of magnetic subsystem [1]. The additional propagation term appear in magnetic dynamic structure factor which result in appearance of two brilluen peaks. Without external magnetic field the coupling of liquid and magnetic subsystems disappears, that immediately reflects in time correlation functions structure. Conclusions about smallness mutual correlations and magnetostriction effects gave a possibility to consider kinetics only for magnetic subsystem [2]. On the basis of two dynamical variables (magnetic moment density and its time derivative) there was demonstrated the phenomenon of changing diffusive dynamics to the spin-wave propagation regime. The characteristic wave numbers of such transition was calculated. The structure factor found has the peculiarities in structure corresponded to the spin-wave excitations. On given model analysed the results of computer simulations, that as whole bear out got results.
1. I. Mryglod, R. Folk, S. Dubyk, Yu. Rudavskii, Physica A, 2000, V. 277, No 3-4,
pp. 389-404.
2. I. Mryglod, S. Dubyk, Yu. Rudavskii, J. Phys. Stud., 2000 (submitted).