Family of paramagnetic centers of Ce$^{3+}$ ions in yttrium aluminum garnet

The electron paramagnetic resonance (EPR) spectra of Ce$^{3+}$ ions in single crystals of yttrium aluminum garnet have been investigated. It has been found that, in addition to the usually observed EPR signals of Ce$^{3+}$ ions located in the regular environment at dodecahedral sites of the crystal lattice, the spectra contain a group of less intense anisotropic lines with $g$-factors close to the corresponding parameters of Ce$^{3+}$ ions in the regular environment. It has been concluded that the observed satellite lines belong to the family of Ce$^{3+}$ ions in the immediate vicinity of which there are permutation defects that lead to a change in the strength and symmetry of the crystal field in the vicinity of the paramagnetic center.