Quartet of resonance peaks of dislocation displacements in NaCl crystals during their magnetic processing in the low-frequency EPR scheme

Resonance relaxation displacements of dislocations have been studied in NaCl crystals placed in crossed ultralow magnetic fields have been studied in the electron paramagnetic resonance (EPR) scheme, i.e., in the static magnetic field $B=(26$–$261)\,\mu$T and the perpendicular radio-frequency field (with the amplitudes of $2.5$ and $6$ $\mu$T in the frequency range $\nu=(0.5$–$7.3)$MHz). The spectrum (quartet) of equidistant resonance peaks of the dislocation mean paths $l(\nu)$ has been observed. In the most part of the studied field interval $B$, the frequencies of the EPR peaks correspond to the Zeeman splitting of the levels with four $g$-factors close to $2$ and the difference of the neighboring values $\Delta g = 0.09$. The equidistance is violated only at the lowest fields, $B<50\,\mu$T, and frequencies $\nu< 0.7\,$MHz.