Magnetic properties of magnetite arrays produced by the method of electron beam lithography

Arrays of magnetite particles in the submicron range (0.1–4.0 µm) have been produced. A novel method involving the utilisation of Electron Beam Lithography techniques often employed in the engineering design of integrated circuits of microchips was used. The fabrication process involved first producing arrays of iron (Fe) particles and then converting them to magnetite (Fe 3 O 4 ) by thermal treatment. The fabricated magnetite particles have well controlled parameters including inter‐particle spacing, an impossible task to achieve using artificially produced powders often employed in rockmagnetic studies. Two methods of converting Fe to Fe 3 O 4 by annealing were used. One method led to Fe 3 O 4 grains with high coercivities, typical of stressed grains and the other low coercivities in agreement with those for laboratory grown crystals. The crystal unit cell edge. Curie temperature, and saturation isothermal remanent magnetisation (SIRM) intensity observed at the Verwey transition are all consistent with stoichiometric magnetite.