Surface damage in a Mn-Zn ferrite induced by laser chemical etching

Surface damage induced by laser etching of a Mn-Zn ferrite has been investigated by Rutherford backscattering spectrometry and proton-induced x-ray emission measurements. It is found that laser-induced etching of the Mn-Zn ferrite in both CCl₄ gas and H₃PO₄ could cause surface damage that is much less than that induced by mechanical polishing. The laser-induced surface damage is distributed in a thin surface layer with a thickness of 50 nm. It is also found that the surface damage is caused by thermally activated lattice dislocation and impurity doping due to the laser irradiation instead of the chemical reactions between etchant chemicals and the ferrite surface. There are two different sources of damage: one is the interstitial atoms from the ferrite substrates; another is from interstitial impurity atoms resulting from the etching process. The study also indicates that the surface damage could reduce the magnetization of the substrate surface.