Mössbauer Effect inDy161in Metallic Dysprosium, DyFe2, and DyAl2

Abstract

The recoilless absorption spectra of the 26-keV $\ensuremath{\gamma}$ rays from ${\mathrm{Dy}}^{161m}$ in ${\mathrm{Dy}}^{161}$ situated in Dy metal, Dy${\mathrm{Fe}}_{2}$, and Dy${\mathrm{Al}}_{2}$ were measured at various temperatures. A value of (-825\ifmmode\pm\else\textpm\fi{}30) Mc/sec was found for the magnetic hyperfine constant (${g}_{0}{\ensuremath{\mu}}_{n}{H}_{\mathrm{eff}}$) of the ground state of ${\mathrm{Dy}}^{161}$ in Dy metal at 20\ifmmode^\circ\else\textdegree\fi{}K. This value is in very good agreement with the free-ion value calculated for the ${\mathrm{Dy}}^{3+}$ ions in the fully magnetized state (${J}_{z}=J$) from data on electron spin resonance in dilute salts. The internal magnetic field acting on the Dy nucleus in Dy${\mathrm{Fe}}_{2}$ at magnetic saturation is (14\ifmmode\pm\else\textpm\fi{}2)% higher than in Dy metal. The magnetic field acting in Dy${\mathrm{Al}}_{2}$ at magnetic saturation is the same, within the experimental errors, as in Dy metal. The ratio of the magnetic moments of the 26-keV level and the ground state of ${\mathrm{Dy}}^{161}$ was found to be -1.19\ifmmode\pm\else\textpm\fi{}0.05. An isomeric shift of (2.5\ifmmode\pm\else\textpm\fi{}0.4) mm/sec was found between Dy metal and ${\mathrm{Dy}}_{2}$${\mathrm{O}}_{3}$ absorbers. The isomeric shifts of Dy${\mathrm{Al}}_{2}$ and Dy${\mathrm{Fe}}_{2}$ absorbers relative to a ${\mathrm{Dy}}_{2}$${\mathrm{O}}_{3}$ absorber were found to be (0.4\ifmmode\pm\else\textpm\fi{}0.4) mm/sec.