Figure 2

Experimental Set-up—(a) Schematic of grazing incidence pump–probe experiment (left panel) with the right panel showing the incidence angles of the pulses where the penetration depth of the laser (red) is 30 nm and the (–101) peak is probed by the X-FEL source (gold). Based on the FeRh refractive index, the X-rays are expected to probe to a depth of 100 nm from the surface of the film at a 0.7° incidence angle, assuming an X-ray attenuation of < 10% by the Pt capping layer (< 3 nm). The strained portion of the film adjacent to the substrate does not contribute to the measured X-FEL diffraction. (b) FeRh epitaxial growth on MgO when orientated 45° to [001]. (c) Pixel maps of the 2D detector for the region of interest (ROI) around the (–101) diffraction peak at an energy of 6.4 keV for a delay time between the pump and probe of 8 ps. (i) The peak for the unexcited sample is shown, (ii) which is compared to the same peak when the sample is excited by laser fluences of 9.4 mJ cm^-2.