Generation Modes of Eu2+ 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 Eu2+ 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.