Contrary to the popular belief that bulk insulators cannot be analyzed by the atom probe technique, we have demonstrated that atom probe analysis of bulk insulating ceramics is possible by using ultraviolet femtosecond pulse laser. For the demonstration, spark plasma sintered yttoria-stabilized t-ZO2-MgAl2O4 nanocomposite material was used. Needle like specimens for field ion microscopy and atom probe analysis were prepared from the bulk sample using the focused ion beam technique. Three dimensional elemental distributions from both the zirconia and spinel have clearly demonstrated that the laser assisted field evaporation yield quantitative atom probe tomography.

(a) SEM BSE image of a tip specimen prepared by the FIB technique from a bulk ZrO₂-MgAl₂O₄ nanocomposite ceramic.
(b) Ne field ion image of the specimen observed after the atom probe analysis.

3DAP map of Al, Mg, Y, Zr, and O taken from the ZrO₂-MgAl₂O₄ nanocomposite ceramics.　(a) and (b) are the concentration depth profiles determined from the inset box (a) and (b).

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Atom probe tomography of Al(green) and Mg(blue) atoms with a volume of ~65×65×270 nm³.
The grain boundary segregation of Al and Mg can be clearly seen on the right-hand side.