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Magnetic structures (magCIF) version 0.9.8
Category ATOM_SITE_MOMENT_SPECIAL_FUNC
Name:'ATOM_SITE_MOMENT_SPECIAL_FUNC'
Parent category:
MAGNETIC
Definition:
Data items in the ATOM_SITE_MOMENT_SPECIAL_FUNC category record details about the magnetic modulation of an atom site in a modulated structure when it is not described by Fourier series. Special functions are effective in some cases where the modulations are highly anharmonic, since the number of parameters is drastically reduced. However, they are in general discontinuous or with discontinuous derivatives and therefore these functions describe an ideal situation that never occurs in a real modulated crystal. Up to now, only a few types of special functions have been used and all of them come from the JANA suite of programs. Although this approach is far from being general, it has the advantage that the functions are tightly defined and therefore the relevant parameters can be calculated easily. In this dictionary, only the special functions available in JANA2000 have been included. These are: (1) Sawtooth functions for atomic displacive modulation along x, y and z. (2) Crenel functions for the occupational modulation of atoms and rigid groups. Both of these only apply to one-dimensional modulated structures. Analogous tags: _atom_site_displace_special_func.*, _atom_site_occ_special_func.*
Category is of type Loop
Category key:_atom_site_moment_special_func.atom_site_label