Figure 5

FWHM of TR-XRD Peak—(a) Model showing how the FWHM of the FeRh (-101) peak is expected to change with probe delay following laser heating to 400 K. The transition is first order and the ratio of AF:FM peak intensity changes with temperature according to the ratio of the two phases based on the magnetometry data of Fig. 1c. The inset shows the expected intensity of the AF and FM peaks several ps after laser excitation. The peak shift and change in FWHM are extracted from a Gaussian fit to the summation of the peaks. (b) Change in FWHM of (–101) peak as a function of probe delay for different laser fluences. The initial peak in the data points to the greatest mixing of the two phases. A longer trend is seen for higher fluences which we ascribe to thermal diffusion in the sample. We note that, irrespective of laser fluence, a small drop in the FWHM is observed in the first few ps after laser excitation, inset for the two highest fluences.