Studying surfaces and thin films using Moessbauer spectroscopy

Using a series of bi-layer samples, we show how Conversion Electron Moessbauer Spectroscopy (CEMS) and X-ray Backscatter Moessbauer Spectroscopy (XBS) can be done with the same experimental set up. The penetration depths of the K and L conversion electrons are measured as 51(6) and 330(240) nm, respectively, with relative contributions of 88(9) and 12(9)%. The penetration depth of the Fe-Kα X-ray signal is determined to be 3.6(2) μm. As a demonstration we show data on surface damage effects in electropolished TRIP steels, and by comparing CEMS and XBS Moessbauer patterns we estimate the thickness of a damaged layer (created by sanding) to be 550(50) nm.