Magnetic Moment of the 99-keV First Excited State ofPt195

Abstract

The Mössbauer effect in ${\mathrm{Pt}}^{195}$ was measured at 20°K with a ${\mathrm{Au}}^{195}$ source electroplated onto a platinum foil and ${\mathrm{Pt}}_{0.1}$ ${\mathrm{Fe}}_{0.9}$, ${\mathrm{Pt}}_{0.3}$ ${\mathrm{Fe}}_{0.7}$, ${\mathrm{Pt}}_{0.5}$ ${\mathrm{Fe}}_{0.5}$, and ${\mathrm{Pt}}_3$Fe absorbers. A split absorption spectrum was observed for the first three absorbers, while ${\mathrm{Pt}}_3$Fe showed no hyperfine structure. The absorption spectrum of the body-centered cubic ${\mathrm{Pt}}_{0.1}$ ${\mathrm{Fe}}_{0.9}$ is compatible with an internal field at the platinum nucleus in the range [$1.2\times {10}^6<~H<~2.9\times {10}^6$]Oe and a ratio of the excited- to ground-state magnetic moments $-1.5\mathrm{}<~\frac{{\mu }_e}{{\mu }_g}<~+0.3\mathrm{}$. The measurement by Ho and Phillips of the internal field in a sample of ${\mathrm{Pt}}_{0.03}$ ${\mathrm{Fe}}_{0.97}$, $H=1.39\mathrm{}\times {10}^6$, can be taken as an upper limit for the field value in the ${\mathrm{Pt}}_{0.1}$ ${\mathrm{Fe}}_{0.9}$ sample. The present results can thus be combined with the Ho-Phillips measurement and with the measured ground-state moment to give $-0.9\mathrm{} \mathrm{nm}<~{\mu }_e<~-0.7\mathrm{} \mathrm{nm}$. The Mössbauer fractions $f$ at 20°K for these absorbers were determined to be (26.9±4.1)%, (24.3±2.6)%, (11.6±0.8)%, and (9.6±1.0)%, respectively.