Nuclear Bragg reflection of 57FeBO3 in radio-frequency magnetic field observed with Si-APD linear array detector

We observed nuclear Bragg reflection by (FeBO3)-Fe-57 (333) with an external radio frequency (RF) magnetic field using a 64 pixel silicon avalanche photodiode linear array detector. The reflection was caused by gamma rays resonantly emitted from Fe-57 nuclei using synchrotron X-rays of 14.413 keV. When an RF magnetic field of only 1.0 Oe at 8.0 MHz was applied to an (FeBO3)-Fe-57 single crystal, a stripe structure of 0.12 mm pitch was distinguished from the intensity distribution with a 30 mu m spatial resolution (full width at half-maximum (FWHM)) of the detector system. Simultaneously, the detector revealed that a decay time of the reflection increased from 15.0 to 35.6 ns with a 0.5 ns time resolution (FWHM). We consider that a magneto-acoustic wave excited on the crystal surface slightly changed the energy of the atomic vibration to partly collapse the speed-up effect caused by the nuclear multiple scattering. (C) 2018 The Japan Society of Applied Physics