Temperature Dependence of theFe57hfs in FeF2below the Néel Temperature

摘要: The temperature dependence of the ${\mathrm{Fe}}^{57}$ hfs in Fe${\mathrm{F}}_{2}$ has been obtained with M\"ossbauer effect antiferromagnetic region. Data just below N\'eel yield a critical exponent $\ensuremath{\beta}=0.325\ifmmode\pm\else\textpm\fi{}0.005$ and $D=1.36\ifmmode\pm\else\textpm\fi{}0.03$. This value $\ensuremath{\beta}$ differs slightly from that 0.333\ifmmode\pm\else\textpm\fi{}0.003 found Mn${\mathrm{F}}_{2}$ by Heller. However, this latter also provides an adequate fit to our data, but over more restricted range temperature. $D$ is larger than previously reported other materials because magnetic anisotropy Fe${\mathrm{F}}_{2}$. In low-temperature region (0-50\ifmmode^\circ\else\textdegree\fi{}K), present measurements are good agreement precise determination ${\mathrm{F}}^{19}$ NMR Jaccarino, indicating both reflect sublattice magnetization.