Mn 55 Nuclear Magnetic Resonance in Mn F 2 —The Suhl-…
1969; American Institute of Physics; Volume: 177; Issue: 2 Linguagem: Inglês
10.1103/physrev.177.667
ISSN1536-6065
AutoresHiroshi Yaśuoka, Tin Ngwe, V. Jaccarino, H. J. Guggenheim,
Tópico(s)Inorganic Fluorides and Related Compounds
ResumoThe NMR of ${\mathrm{Mn}}^{55}$ in antiferromagnetic Mn${\mathrm{F}}_{2}$ has been reexamined, using both superregenerative and pulsed NMR techniques, in the temperature region 1.3-20\ifmmode^\circ\else\textdegree\fi{}K. Instead of the single resonance originally reported, five distinct quadrupolar-split transitions are observed, whose separation yields a value of $\frac{{e}^{2}\mathrm{qQ}}{\ensuremath{\hbar}}=11.7\ifmmode\pm\else\textpm\fi{}0.3$ MHz. The frequency of the 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 in the hyperfine interaction in going from Zn${\mathrm{F}}_{2}$: Mn to Mn${\mathrm{F}}_{2}$, this would imply $\frac{{〈{S}_{z}〉}_{0}}{S}=(99.41\ifmmode\pm\else\textpm\fi{}0.03)%$ in the antiferromagnetic ground state. The magnitude and $m$ dependence of the linewidths of the individual transitions are reasonably consistent with the predictions of the Suhl-Nakamura theory (i.e., the indirect nuclear spin-spin interaction via virtual spin-wave excitations). The failure to observe a transient signal is attributed to the very short ${T}_{2}(<1 \ensuremath{\mu}sec)$ resulting from the latter interaction.
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