Pure nuclear reflexes and combined hyperfine interactions in YIG

Winkler, H.; Eisberg, R. M.; Alp, E.E.; Rüffer, R.; Gerdau, E.; Lauer, S.; Trautwein, Alfred X.; Grodzicki, Michael; Vera, A.

doi:10.1007/bf01301594

Cited by 56 publications

(10 citation statements)

References 27 publications

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“…It was found that the hyperfine magnetic field in our sample was 370 ±4 kG, 7.5% smaller than the published value of 400 kG. 19 This was confirmed in an independent 9 OCTOBER 1989 Mossbauer absorption experiment. The reduced field is believed to be due to a substantial amount (4%) of Pb impurity introduced in order to minimize strains in the 57 Fe-enriched YIG crystal grown epitaxially on a gadolinium gallium garnet substrate.…”

Section: Pulses Of Synchrotron X Rays From the Ib Undulator At The Pesupporting

confidence: 83%

Resonance energy shifts during nuclear Bragg diffraction of x rays

Arthur

Brown

et al. 1989

Phys. Rev. Lett.

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We have observed dramatic changes in the time distribution of synchrotron x rays resonantly scattered from 57 Fe nuclei in a crystal of yttrium iron garnet, which depend on the deviation angle of the incident radiation from the Bragg angle. These changes are caused by small shifts in the effective energies of the hyperfine-split nuclear resonances, an effect of dynamical diffraction for the coherently excited nuclei in the crystal. The very high brightness of the synchrotron x-ray source allows this effect to be observed in a 15-min measurement. PACS numbers: 76.80.+y, 07.85.+n, 42.10.Qj, 61.10.DpWhen the 14.4-keV Mossbauer resonance in 57 Fe in a Bragg-diffracting crystal is excited by a short, broadband pulse of radiation from a synchrotron light source, the time distribution of the diffracted radiation exhibits a beat pattern due to interference between the coherently excited nuclear hyperfine levels. 1 " 4 Analysis of this time distribution gives a very accurate determination of the hyperfine fields in the crystal.We have used an undulator beam line at the PEP storage ring at Stanford Synchrotron Radiation Laboratory (SSRL) to resonantly scatter x rays from 57 Fe in a nearly perfect crystal of yttrium iron garnet (YIG). The high brightness of this x-ray source allowed us to obtain a time distribution with excellent statistics in less than 15 min, with a data collection rate nearly 2 orders of magnitude higher than in previous experiments of this type 2,3,5-7 Along with the beat pattern due to the hyperfine splitting of the nuclear resonance, we observed dramatic changes in the time distribution that depend sensitively on the deviation of the incidence angle of the radiation from the Bragg angle. These changes are due to small shifts in the effective resonance energies of the collection of Fe nuclei in the crystal lattice, an effect of dynamical diffraction, and are the subject of this Letter.Analysis of the dynamical diffraction theory for a perfect lattice of simple resonant nuclei shows that the resonance energy plays a role complementary to that of the diffracting wave vector, since the crystal reflectivity depends strongly on both the angular deviation from the Bragg angle and the energy deviation from the resonance energy. For both resonant and nonresonant scattering, the reflectivity of a thick crystal in Bragg geometry is maximized when the quantity [(a -2go) 2 -4g£] 1/2 is minimized, 8 " 10 where a is proportional to the deviation of the incident radiation from the Bragg angle, go is the scattering amplitude in the forward direction, and gK is the scattering amplitude in the reflected direction (this assumes that the crystal is centrosymmetric). The scattering amplitude for nonresonant electronic scattering is KV where Kis the unit-cell volume and F e (K) is the complex electronic scattering length of the unit cell, including the geometrical structure factor, electronic form factors, imaginary electronic absorption factors, and DebyeWaller temperature factors. In contrast, the energydependent scatteri...

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Section: Pulses Of Synchrotron X Rays From the Ib Undulator At The Pesupporting

confidence: 83%

Resonance energy shifts during nuclear Bragg diffraction of x rays

Arthur

Brown

et al. 1989

Phys. Rev. Lett.

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“…6 have been obtained by the transmission integral technique taking polarization effects into account. 19 C. Magnetically perturbed spectra of polycrystalline material at 3.8 K To confirm the results of the single crystal experiments, we have measured Mossbauer spectra of a polycrystalline absorber at 3.8 K in applied magnetic field of 2.5 and 6.7 T perpendicular to the gamma ray direction. (14) to calculate the expectation values of the spin.…”

Section: B Magnetically Perturbed Single Crystal Spectra At Rtmentioning

confidence: 76%

Single crystal and magnetic Mössbauer studies on [(C6H5)4P][(C6H5CH2)–(CH3)3N][Cl2FeS2MoS2]

Winkler

Bill

Lauer

et al. 1985

The Journal of Chemical Physics

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“…The YIG magnetic crystal structure allowed us to observe pure nuclear resonant scattering from a ferromagnetically aligned subset of 57 Fe nuclei [7]. A small external magnetic field was used to orient the internal ferromagnet field perpendicular to the scattering plane, so that the rotation angle of the scattered photons around the nuclear quantization axis was equal to 20 B -In a magnetic field, the 14.4-keV 57 Fe nuclear resonance is generally split into a hyperfine six-line spectrum (see Fig.…”

Section: Y/(t+at)=e-ihat/h Yf(t)mentioning

confidence: 99%

Phase shift of a rotated quantum state observed in an x-ray scattering experiment

et al. 1992

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The rotation of the reference frame of a particle is known to lead to a phase change of its wave function proportional to its angular momentum. This can manifest itself as an angle-dependent phase shift of a photon scattered by a fixed target, when the photon state is an eigenstate of the component of total angular momentum perpendicular to the scattering plane. This phase shift has been observed in the quantum beat pattern resulting from the transient excitation of 57 Fe nuclei by synchrotron radiation. PACS numbers: 03.65.-w, 42.25.Hz, 76.80.+y, 78.70.Ck Quantum wave functions and classical wave fields reflect the symmetries of space and time that result in conservation laws and phase factors involving the conserved quantities. For example, the homogeneity of time leads to the conservation of energy and the uniformity of space leads to the conservation of total linear momentum for an isolated system. Such systems are invariant under translations in time or space, and the translated wave functions acquire phase shifts depending on the conserved values [1,2]. For simple eigenstates of energy and linear momentum,

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Pure nuclear reflexes and combined hyperfine interactions in YIG

Cited by 56 publications

References 27 publications

Resonance energy shifts during nuclear Bragg diffraction of x rays

Resonance energy shifts during nuclear Bragg diffraction of x rays

Single crystal and magnetic Mössbauer studies on [(C6H5)4P][(C6H5CH2)–(CH3)3N][Cl2FeS2MoS2]

Phase shift of a rotated quantum state observed in an x-ray scattering experiment

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