Effect of pressure on the magnetic properties ofU(In1−xSnx)3:Moment suppression inU(In0.6Sn0.4)3

Abstract

The volume dependence of the magnetic properties of $\mathrm{U}({\mathrm{In}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}{)}_{3},$ with $x=0.2$ and 0.4, has been studied using ${}^{119}\mathrm{Sn}$ nuclear forward scattering of synchrotron radiation and M\"ossbauer spectroscopy at high pressures up to 25 GPa. The results show that in $\mathrm{U}({\mathrm{In}}_{0.8}{\mathrm{Sn}}_{0.2}{)}_{3}$ the $5f$ magnetic moment is almost localized. Pressure induces an increase of the N\'eel temperature, while the transferred magnetic hyperfine field shows no change. Conversely, in $\mathrm{U}({\mathrm{In}}_{0.6}{\mathrm{Sn}}_{0.4}{)}_{3}$ the transferred field decreases monotonically with increasing pressure and the N\'eel temperature goes through a maximum, showing a clear delocalization of the $5f$ electrons. This is discussed in terms of $5f$-ligand hybridization and appears to lead to the formation of a high-pressure state characterized by strong dynamical spin correlations.