Magnetocrystalline Anisotropy of Europium Sulfide

Abstract

The first- and second-order magnetocrystalline anisotropy constants, ${\mathrm{K}}_{1}$ and ${K}_{2}$, of EuS were measured by a ferromagnetic resonance technique. The measurements were performed at 21.48 GHz and 1.35\ifmmode^\circ\else\textdegree\fi{}K, and the sample was a small, highly polished strain-free single-crystal sphere, oriented so that the (110) plane contained both the rf and static magnetic fields. The linewidth was of order 10 Oe, the narrowest observed in a chalcogenide of europium and indicates the degree of perfection and purity of the sample. $\frac{{K}_{1}}{M}$ and $\frac{{K}_{2}}{M}$ (where $M$ is the saturation magnetization) were determined to be -19.6\ifmmode\pm\else\textpm\fi{}1.0 and -4.6\ifmmode\pm\else\textpm\fi{}0.3 Oe, respectively. The cubic crystal-field splitting parameters ${b}_{4}$ and ${b}_{6}$ were calculated on the basis of Wolf's single-ion mechanism, and were determined to be (0.268\ifmmode\pm\else\textpm\fi{}0.014) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$ and (-0.019\ifmmode\pm\else\textpm\fi{}0.09) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$ ${\mathrm{cm}}^{\ensuremath{-}1}$, respectively. The results are compared with the behavior of the ${\mathrm{Eu}}^{++}$ ion in cubic host lattices.