Gravitational redshift experiments with the high-resolution Mössbauer resonance in67Zn

A gravitational tedshift (GRS) experiment using the high-resolution Mössbauer resonance in⁶⁷Zn is described. The tiny Doppler motion of the source can be checked by a dc-SQUID based displacement sensor. The results on the GRS strongly indicate that solid-state effects, which are difficult to control experimentally, finally limit the accuracy that Mössbauer measurements can provide in determining the GRS. We argue that for this reason conventional Mössbauer experiments most probably will not be able to compete with other methods in future GRS measurements of very high precision.     

Preparative and Mössbauer studies of Bi2Sr2Ca n-1Cu n O y compounds withn=2 or 3

The influence of sintering temperatures and nominal starting compositions on the phase contents of polycrystalline Bi₂Sr₂Ca _n-1Cu _n O_4+2n samples are reported. After every sintering the samples were characterized with X-ray diffraction and magnetic AC susceptibility measurements. For Mössbauer studies, in each case also a corresponding specimen containing⁵⁷Fe was synthetized. The identification of various superconducting Bi₂Sr₂Ca _n-1Cu _n O_4+2n phases on the basis of Mössbauer spectra consisting usually of three quadrupole doublets is discussed.     

Studies of hyperfine interactions inRBa2(Cu1-x 57Fex)3O7-δ high-T c superconductors

Both⁵⁷Fe and¹⁵¹Eu Mössbauer resonances were used to study polycrystallineRBa₂Cu₃O_7-δ samples. The dependence of hyperfine interaction parameters on the oxygen deficiency δ is studied in detail with¹⁵¹Eu. For⁵⁷Fe spectra, a site assignment is proposed.     

Influence of high-frequency magnetic fields on Mössbauer resonance

The influence of high-frequency magnetic modulation on Mössbauer resonance is investigated using the⁶⁷Zn resonance. A phase-modulation theory theory explaining the experimental results is presented. Implications to magnetic modulation experiments with the⁵⁷Fe resonance are also discussed.     

Phase modulation of recoilless gamma radiation by nuclear zeeman effect

The use of an alternating magnetic field for phase modulation of recoilless gamma radiation is studied. The measurements were performed with the Mössbauer resonances of Fe-57 and Zn-67. Novel time-domain data are presented from experiments on the nuclear Zeeman effect at high modulation frequencies.     

On the enhancement of the recoilless fraction in restricted geometries

The enhancement of recoilless fraction (f factor) in restricted geometries is studied. The experiments were carried out using the¹¹⁹Sn resonance in SnCl₄ molecules trapped in porous glass. A theoretical approach to explain the increase of thef factor is presented.     

Influence of high-frequency modulation on Mössbauer resonance: Experiments with67Zn

Hyperfine Interactions - Temporal aspects related to the Mössbauer resonance are reviewed, in particular time-dependent transient effects produced by high-frequency modulation of the...