Dear Alexander,
This is theoretically one of the few things that can be done with PRODD,
which is a refinement program based on the CCSL subroutine library. Some
multibank spiral structure refinements were done with the program when I
was doing my thesis.
1) How do I decide on the space group? With incommensurate structures is it
always just P -1
I don't think it is always P-1. With CCSL you either have symmetry
elements as part of the magnetic symmetry, or not, called MSYM or NSYM.
It was rather difficult to figure out.
5) Atom types: Where in the manual do I find the correct types I have to use?
Is it always just M in front of the atom?
With CCSL you look up the magnetic form factors and put them in the
input file with whatever names you like :-)
Sorry I can't help much on the fullprof questions. Since you seem to
have a multi-k structure, for PRODD you would need at least two phases
to do that. I remember spending some time trying with fullprof but
eventually learned a valuable lesson about why source code is useful. If
you like, I'd be happy to send you the PRODD sources and try to dig out
some examples. Even better, you could tidy the sources up and merge them
with the current CCSL, realistically I am never going to find the time
to do it myself.
Spiral magnetic structures are a fantastic way to learn about
crystallography and reciprocal space. Good luck!
Jon
