Mössbauer Effect Studies of the 103-keV Level onEu153

The recoilless absorption spectra of the 103-keV $\gamma$ rays from ${\mathrm{Eu}}^{153m}$ in ${\mathrm{Eu}}^{153}$ situated in europium oxide and in europium iron garnet were measured at 20°K. The source used was ${\mathrm{Sm}}^{153}$ in the form of an oxide at 20°K. With the ${\mathrm{Eu}}_2$ ${\mathrm{O}}_3$ absorber an unsplit absorption line with (2.1±0.4) mm/sec width at half-maximum was obtained. From the hyperfine Zeeman splittings obtained with the europium iron garnet absorber, a value of (+2.01±0.09) nm. was found for the magnetic moment of the 103-keV level of the ${\mathrm{Eu}}^{153}$. This value is in very good agreement with the predictions of the unified model.