Generation modes of Eu$^{2+}$ nonequilibrium dimers and influence of a magnetic field on their reconstruction in NaCl: Eu crystals

Three generation modes have been experimentally revealed for impurity-vacancy Eu$^{2+}$ dimers with the atomic structure determined by the spin-selective transitions to equilibrium configurations in a constant magnetic field of 5–15 T in NaCl: Eu crystals. It has been shown that, under conditions of linearly increasing mechanical stresses, the plastic strain of the NaCl: Eu crystals accelerates the aggregation of impurities and generates magnetically sensitive dimers several tens of times more rapidly than in the case of diffusion-controlled aggregation. Under conditions of linearly increasing strains, magnetically sensitive dimers arise as a result of the destruction of impurity precipitates by moving dislocations. The identification of dimers and the determination of their average spin in the process of spin-dependent reorganization of the atomic structure of the dimers have been performed using optical spectroscopy and SQUID magnetometry.