These files should contain the main parameters of elements or compounds materials.
The format is the following:

The file name should look like "SiO2.txt" (and should be meaningful).
The ".txt" extension is mandatory.
The file content should be the following :

1st line : a short description of what this description actually represents
2nd line : atomic or cells density (in 1e28 m-3)
3rd line : neutron scattering length bn (in fm)
4th line : neutron absorption cross section TAB the corresponding energy in meV
5th line : the real form factor for x-rays TAB the corresponding energy in eV
6th line : the real form factor for x-rays TAB the corresponding energy in eV
7th line : magnetisation in µB/unit cell
8th line : # a more detailed description of where the data came from in the case 
           of "fitted data" for example

NOTA : if lines 5 or 6 are not provided (that is do not contains any numerical values), 
       the programs will refer to the tabulated data in the folder FormFactors
       (NOT YET IMPLEMENTED!)
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To be done
Add Permalloy

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Useful 

N = 6.022E23
atomic density = d * N / A
