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

Abstract

The crystallographic and magnetic structures of Ho₂Fe₉Ga_8−xAl_x (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 $\text{R}\text{3}\text{m}$). The magnetic moments of all the phases below the Curie temperature show uniaxial anisotropy.