The influence of weak electric fields on the magnetically induced mobility of individual dislocations in NaCl crystals has been investigated. It is shown that the strong influence of an electric field on the magnetoplasticity, which is caused by the transformation of impurity centers at dislocations from the diamagnetic state (Me (++)) to the paramagnetic state (Me (+)), has both bulk and surface components. The surface effect dominates over the bulk one in weak electric fields (E < 0.5 kV/m), which are insufficient for the exciting bulk electromigration of charged defects near dislocations. However, the contribution of the surface effects becomes insignificant in comparison with the bulk processes in stronger fields E. Lacquering crystal faces to block the surface electromigration of defects excludes this stimulation component at any E. It is shown that dislocation motions occurring due to a rapid switching on an electromagnet also disappear in lacquered samples. These effects observed may be related to the same surface electromigration of defects under the vortex electric fields induced by switching on a magnetic field.
展开▼
