Isotopic Correction of Compositional Inaccuracies in the Atom Probe Analysis of LaB₆

The atomic-scale characteristics of stoichiometric lanthanum hexaboride (LaB₆) material are investigated in this work using atom probe tomography (APT). The presence of a higher background level in the mass spectrum is attributed to continuous boron evaporation, causing preferential boron loss and affecting composition measurements. The measured composition in LaB₆ exhibits inaccuracies influenced by the experimental conditions, particularly showing an excess of lanthanum (La). This enrichment is consistently linked to boron’s tendency for continuous evaporation, leading to a higher fraction of multiple evaporation and detection events. Consequently, the susceptibility of boron to measurement errors is increased due to detector limitations. To address this issue, we propose a method of compositional correction based on pseudomultiple events and an abundance of isotopic pairs, which has been successfully applied to elements with two isotopes and has the potential for elements with multiple isotopes.