Section and stroboscopic diffraction imaging of the magneto-acoustic vibrations in FeBO3 by synchrotron radiation

Ultrasonic waves, excited in an FeBO3 crystal via magneto-elastic coupling, were visualized using synchrotron radiation diffraction imaging (`topography'). In particular, restricted volume images were used in order to distinguish the contribution of the various parts of a thin (50 µm) sample to the diffracted beam. The magnetic field dependence of the sound velocity was then exploited to tune the FeBO3 crystal at a resonance four times the ESRF single bunch frequency, allowing stroboscopic section imaging and the deconvolution of the time-integration effect. This set of experiments confirmed that the vibrating crystal model used to explain the focusing of x-rays in FeBO3 at certain resonances is correct.