Nuclear resonance scattering of synchrotron radiation by two non-equivalent crystal sublattices in 57Fe3BO6\mathrm{^{57}Fe_3BO_6}

Pure nuclear Bragg reflections off a single crystal of $^{57}Fe_3BO_6$ consisting of two antiferromagnetic sublattices were studied using Mössbauer and synchrotron radiation. Energy and time spectra were measured of different reflections (h00), when either only one sublattice was reflecting, (300), or both sublattices at comparable strength either in antiphase, (500), or in phase, (700). Characteristic line shapes and quantum beat modulations revealed the interference of the scattering by the two sublattices

Nuclear Diffraction of Synchrotron Radiation in Laue Geometry: Quantum Beat Shift

Time spectra of nuclear resonant diffraction of synchrotron radiation in nearly perfect single crystals of $^{57}FeBO_3$ and $^{57}Fe_3BO_6$ have been measured in Laue geometry. Characteristic shifts of the quantum beat pattern proportional to the crystal thickness were observed. This shifts originate from the thickness dependence of the relative phases of the interfering hyperfine components of the scattered radiation. The phase velocities of the components are different because of a complicated dispersion law where all 14.4 keV nuclear hyperfine transitions of $^{57}$Fe contribute to the scattering amplitudes. A kind of interferometry employing beam splitting in energy was demonstrated in the experiment

Time spectra of a nearly-single-line pure nuclear reflection excited by synchrotron radiation

The time dependence of the coherent response of a $^{57}$FeBO$_3$ single crystal excited by synchrotron-radiation (SR) pulses was studied in the pure nuclear (333) Bragg reflection near the Néel temperature, where the Mössbauer reflection spectrum consists of nearly a single line of almost natural linewidth. The time spectra revealed a delayed reemission of γ quanta into the Bragg direction starting at zero intensity. This behavior was determined by two factors: the coherent decay of the nuclear excited state and the interference of two nearly coinciding hyperfine components

Quantum beat dilation due to magnetisation breakdown

The temperature dependence of the magnetisation of a nearly perfect single crystal $^{57}FeBO_3$ was studied in between room temperature and Néel temperature by measuring the time dependence of the nuclear response to a flashlike excitation by pulsed synchrotron radiatio

Shaping of Nuclear Bragg Reflected SR-Pulses by Broad Resonance Absorbers

Time and energy spectra have been studied of Mössbauer filter systems consisting of a pure nuclear reflection $_3FeBO^{57}$(333) in connection with a broad resonance absorber. The energy spectra show how much of each line of the multiplet has been absorbed. The corresponding time spectra show the modified quantum beats to be expected from this, and also display risetime effects revealing the absorber's action. Part of the motivation is to produce simpler wave packets suitable for subsequent analysis of $^{57}$Fe-containing materials