Mn55Nuclear Magnetic Resonance in MnF2—The Suhl-Nakamura Interaction

摘要: The NMR of ${\mathrm{Mn}}^{55}$ in antiferromagnetic Mn${\mathrm{F}}_{2}$ has been reexamined, using both superregenerative and pulsed techniques, the temperature region 1.3-20\ifmmode^\circ\else\textdegree\fi{}K. Instead single resonance originally reported, five distinct quadrupolar-split transitions are observed, whose separation yields a value $\frac{{e}^{2}\mathrm{qQ}}{\ensuremath{\hbar}}=11.7\ifmmode\pm\else\textpm\fi{}0.3$ MHz. frequency central (\textonehalf{} \ensuremath{\leftrightarrow} -\textonehalf{}) transition extrapolates to 670.38\ifmmode\pm\else\textpm\fi{}0.05 MHz at 0\ifmmode^\circ\else\textdegree\fi{}K. Were there no changes hyperfine interaction going from Zn${\mathrm{F}}_{2}$: Mn Mn${\mathrm{F}}_{2}$, this would imply $\frac{{〈{S}_{z}〉}_{0}}{S}=(99.41\ifmmode\pm\else\textpm\fi{}0.03)%$ ground state. magnitude $m$ dependence linewidths individual reasonably consistent with predictions Suhl-Nakamura theory (i.e., indirect nuclear spin-spin via virtual spin-wave excitations). failure observe transient signal is attributed very short ${T}_{2}(l1 \ensuremath{\mu}sec)$ resulting latter interaction.