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Relaxation in the ferromagnetic phase of terbium arsenate (TbAsO 4 )
Author(s) -
Müller P. H.,
Kasten A.,
Schienle M.
Publication year - 1983
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221190128
Subject(s) - condensed matter physics , ferromagnetism , magnetic susceptibility , terbium , ising model , relaxation (psychology) , phase (matter) , magnetic moment , magnetic domain , debye , magnetization , materials science , physics , magnetic field , quantum mechanics , ion , social psychology , psychology
Below T c = 1.5 K TbAsO 4 is an Ising ferromagnet with induced magnetic moments. A superstructure of the magnetic moments found by Schäfer and Will may be explained by very small ferromagnetic domains. A simple estimation of the free energy at T = 0 yields 0.05 μm for the thickness of these domains. In the ordered phase the complex magnetic ac susceptibility is strongly frequency dependent. The relaxation depends on two coupled processes. It is assumed that the process at lower frequencies is due to domain wall shifting and the process at higher frequencies is caused by the internal field. The frequency dependence can be described by an extension of the Debye equation which decouples the two processes. The susceptibility of a system with rigid domain walls is determined in mean field approximation.