I'm using the latest release (version = "fleur 37").

One of the files is too big to be uploaded.
I create this folder here with the out files: "drive.google.com/drive/folders/1MErh5n3GBh_VFeAn3bO3lfYaUKeYoISl?usp=drive_link"

Dear Gregor,

thanks for the reply. Hope you had a good vacation.

I did perform some tests using your input, and also adding local orbitals for the 5s and 5p Gd states (attached inputs).

What I noticed is that the calculations with the local orbitals are the following: they depend on the size of the spheres, if I increase the size of the Ga muffin-tin radius the calculations crashes for some q-values; it also crashes (for some q-values) when considering relativisticCorrections="T".

Now, the trend observed for the energy as a function of q (with and without local-orbitals) are completely different (see figure).
With Gd 5s and 5p states in the core, the lowest energy of the system is ferromagnetic (q=(0,0,0)). When I consider these states as local orbitals, the spin-spiral states have lower energies in the path considered for the calculations.
I wonder: which result would be more reliable, if any?

In the calculations I consider a full k-mesh and only the Identity symmetry.
(The calculations are not very well converged - k-mesh is 6x6x6 - but don't know if just this justifies such different trends).
I'll test later with lda+U and see if these trends are the same.