Evaporation mechanisms of MgO in laser assisted atom probe tomography

In this paper the field evaporation properties of bulk MgO and sandwiched MgO layers in Fe are compared using laser assisted Atom Probe Tomography. The comparison of flight time spectra gives an estimate of the evaporation times as a function of the wavelength and the laser energy. It is shown that the evaporation takes place in two steps on two different time scales in MgO. It is also shown that as long as the MgO layer is buried in Fe, the evaporation is dominated by the photon absorption in Fe layer at the tip apex. Eventually the evaporation process of MgO is discussed based on the difference between the bulk materials and the multilayer samples.

Research Highlights
► Field evaporation properties of bulk MgO are compared with thin film.
► MgO sandwiched between Fe layers.
► Evaporation process in two steps in two different time scales.
► The change in the thickness of the MgO layer(from 4 to 32nm) does not change the evaporation behavior.