Magnetic and crystal structure and magnetocrystalline anisotropy of hexagonal Fe/sub 60/Ga/sub 40-x/As/sub x/ (x= 6, 23) and FeGa/sub 23/Sb/sub 17/ compounds

Powder neutron diffraction at 1.5 K has to investigate the crystal and magnetic structure, whilst the Singular Point Detection (SPD) technique has been used to measure the temperature and composition dependence of the magnetic anisotropy of Fe/sub 60/Ga/sub 40-x/As/sub x/ (x=6, 23) and FeGa/sub 23/Sb/sub 17/. The compounds Fe/sub 60/Ga/sub 17/As/sub 23/ and FeGa/sub 23/Sb/sub 17/ are isotypic with Ni/sub 2/In (P6/sub 3//mmc) and Fe/sub 60/Ga/sub 34/As/sub 6/ is a complex modification of this with a doubling of the lattice constant a of the parent Ni/sub 2/In subcell. The neutron data show that the magnetic structures are planar at 1.5 K. Analysis of the SPD signals also indicates a planar anisotropy for all compositions at low temperatures. The temperature dependence of the anisotropy field HA is very similar for the Ga compounds whilst for the Sb compound a smoother dependence is observed at low temperatures. The anisotropy field increases irrespective of As or Sb substitution. The Curie point, saturation magnetization and anisotropy field can be simultaneously increased by changing the relative content of non-magnetic ions.<
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