MAGNETOPLASTIC EFFECT IN NONMAGNETIC CRYSTALS AND INTERNAL-FRICTION

A new physical phenomenon, the magnetoplastic effect, was found and investigated in a series of non-magnetic crystals (NaCl, CsI, LiF, Zn, Al). The phenomenon manifests itself in dislocation displacements as a result of exposing the specimens to a static magnetic field in the absence of mechanical loading. The effect was studied experimentally as a function of the time of magnetic treatment of the samples, the magnitude and orientation of the magnetic field (B = 0.05-2 T), the temperature (T = 4.2-293 K), the type and concentration of impurities, the density of ''forest'' dislocations and the frequency (v = 0-200 Hz) of the alternating (over orientation) magnetic field. A strong effect of a weak static electric field (E = 2-30 V cm(-1)) on the dislocation mobility in NaCl specimens simultaneously exposed to a static magnetic field (B = 0.1-0.4 T) is found (with no electric influence at B = 0). A physical interpretation of the phenomenon is proposed. Possible manifestations of the magnetoplastic effect in the internal friction are discussed.