Neutron Diffraction Studies of a Nickel Zinc Ferrite

Neutron diffraction studies have been made of a ferrite powder of composition ${\mathrm{Zn}}_{0.5}$ ${\mathrm{Ni}}_{0.5}$ ${\mathrm{Fe}}_2$ ${\mathrm{O}}_4$. The crystal structure is of the spinel type with 4 ${\mathrm{Zn}}^{++}$ and 4 ${\mathrm{Fe}}^{+++}$ ions in the tetrahedral positions and 4 ${\mathrm{Ni}}^{++}$ and 12 ${\mathrm{Fe}}^{+++}$ ions in the octahedral positions. The magnetic structure at 25°C appears to have an antiparallel arrangement of the ${\mathrm{Fe}}^{+++}$ spins on the two sites and a random orientation of the ${\mathrm{Ni}}^{++}$ spins.