Yi. Golovin et al., Influence of a weak magnetic field on spin-dependent relaxation of structural defects in diamagnetic crystals, MAT SCI E A, 288(2), 2000, pp. 261-265
The purpose of the work is to investigate relaxation of residual stresses a
nd metastable point defects and plastic properties of ionic crystals in cro
ssed static and microwave magnetic fields at the paramagnetic resonance con
dition. It is revealed that coincidence of quantum energy of a microwave fi
eld with energy of Zeeman splitting of electronic spin sublevels of paramag
netic centers leads to an increase in relaxation rate of residual stresses
and of metastable point defects, and, as a result, to resonant weakening of
crystals which manifests itself in an increase of dislocation mobility and
macroplastic flow rate, as well as in a decrease of crystal microhardness.
It is shown that the metastable Ca and Eu aggregates sensitive to a static
magnetic field in the absence of microwave fields are responsible for reso
nant weakening. The resonance arises in short-lived non-thermalized states
of these aggregates excited by thermal fluctuations. (C) 2000 Elsevier Scie
nce S.A. All rights reserved.