F.J. Litterst

Analytical solution for the57Fe Mössbauer spectra for octahedral cage hopping and correlated electric field gradient fluctuations

We derive an analytical solution for the Mössbauer relaxation spectra of57Fe in the case of correlated jump diffusion and electric field gradient rotation in an octahedral cage.

Relaxation effects in very dilute Pd(Fe) and Pt(Fe)

Abstract The Mossbauer emission spectra of very dilute Pd( 57 Co) and Pt( 57 Co) reveal fast fluctuations of the 57 Fe hyperfine field. The nuclear orientation parameters are markedly changed in the decay cascade from 57 Co to 57 Fe, as shown for Pd(Fe). The longitudinal electronic relaxation times derived for Pt(Fe) indicate retardation effects for large values of B / T .

Electronic spin relaxation in a superconductor from Mössbauer spectroscopy

Abstract 160Dy Mossbauer hyperfine spectra of dilute Dy3+ in Thorium show an increase of the electronic spin relaxation of the Dy3+ moment directly below the superconducting transition Tc = 1.27 K. A relaxation lineshape theory with frequency dependent relaxation functions based on the BCS model is used for the data analysis.

Moment compensation in NixRh1−x(Fe) from Moessbauer spectroscopy

Abstract The magnetic behaviour of very dilute 57Fe(≈20 ppm) impurities in paramagnetic NixRh1−x (x = 0.42 and x = 0.55) alloys has been studied by Moessbauer spectroscopy in the temperature range between 11 and 0.05 K and in external fields up to 5.6 T. The magnetic moment associated with the Fe-impurity is determined via the dependence of the hyperfine magnetic field on applied magnetic field and temperature. Below 4.2 K deviations from a free spin behaviour are found. The saturation hyperfine field becomes dependent on the applied field, a behaviour which is typical for impurity spin compensation. This compensation decreases with Ni concentration.