Direct NMR measurements of theF19-Mn transferred hyperfine interaction in Mn: PbF2

Abstract

The $^{19}\mathrm{F}$-Mn transferred hyperfine interaction $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{A}$ in Mn: Pb${\mathrm{F}}_{2}$ has been determined by direct observation of the NMR of $^{19}\mathrm{F}$ nuclei nearest neighbor to the ${\mathrm{Mn}}^{2+}$ impurity. The angular dependence of the NMR of three inequivalent sites was studied for applied fields in the (110) plane and was fitted with the values ${A}_{s}=33.82$ MHz and ${A}_{p}=7.82$ MHz. The NMR was unobservable for $Tg2$ K, suggesting rapid electronic spin relaxation. For $Tl1.5$ K, NMR was observed in the eigenstates of the ${\mathrm{Mn}}^{2+}$ with ${S}_{z}=\frac{5}{2} \mathrm{and} \frac{3}{2}$; the linewidth $\ensuremath{\Delta}H$ became temperature independent and probably inhomogeneously broadened, with a pronounced angular variation.