Kolchenko I. Magnetomechanical effect in silicon crystals

The thesis presents the results of investigation of the changes in micromechanical properties of the silicon crystals affected by weak constant magnetic field. For the first time in silicon crystals magnetomechanical effect (MME) have been discovered experimentally. MME consists in changing the microhardness of silicon crystals influenced by magnetic field. The principle of controlling the MME relaxation using X-ray exposure as well as water and chemical solution (Sirtle etchant) has been elaborated experimentally. It has been found that the weak magnetic field acting on the silicon crystals changes the specific surface resistance and gives rise to non-monotonic behavior of its relaxation after the removal of magnetic field. It is established that magnetic treatment of silicon crystals is followed by structural changes: increase in interstitial oxygen concentration and appearance of additional disturbed layers. The obtained results point out the occurrence of new paramagnetic centers in silicon crystals after magnetic treatment. The model approximations have been proposed to provide an explanation for the physical nature of magnetic sensitive effects discovered in silicon crystals, which are based on the action of magnetic field on the structural defect subsystem (intrinsic, impurity defects and its complexes).