Fig. 3

The Fe L-edge EELS analysis of sample #090. a HAADF image after EELS measurements show beam damage except for 0.01 and 0.02 s. b EELS with different dwell times show that the peak intensity around 710 eV increases rapidly with increasing dwell time and the peak of 708 eV is almost invisible at 10 s. Fe²⁺ and Fe³⁺ lines represent L₃ peak positions of Fe²⁺ and Fe³⁺ reference materials, respectively. c Variations of Fe³⁺/ΣFe ratio versus the dwell time. The calculated Fe³⁺/ΣFe value is -3.8% at 10 ms. The negative value is mainly due to the quantitative method errors