High-concentration substitution of Ga and Al in R2Fe17 (RHo or Y): A neutron study of crystallographic and magnetic structure

The crystallographic and magnetic structures of Ho2Fe9Ga8−xAlx (x = 0,4) and Y2Fe9Ga8 were studied by powder neutron diffraction. The atomic fractional occupancies of gallium and aluminum and the magnetic moments of Ho and Fe atoms were obtained by Rietveld structure analysis method. The gallium and aluminum occupy 18f, 18h and 6c sites, but prefer to occupy the 6c and 18f sites (space group R3m). The magnetic moments of all the phases below the Curie temperature show uniaxial anisotropy.