Tilt-Effect in the Electron Drag of Dislocations in Metals

We study the electron drag force acting on a moving dislocation in the presence of strong magnetic field, H. In experiments with zinc crystals (C.M.Kim and J.M.Galligan, Acta mater. 44, 775 (1996).) the H-dependent change in stress exhibits a sharp minimum at φ = 0, where φ is the angle between the magnetic field and the slip plane of dislocations. The peak in stress, which according to (A.M.Grishin et al., JETP, 43, 753 (1976).), should be at φ =0 is shifted by a few degrees from zero. To explain this we calculate the electron drag force taking into account the deformation and electromagnetic mechanisms of the electron-dislocation interaction. We show that the deformation and electromagnetic contributions to the drag force compensate each other at φ = 0 and this provides a sharp minimum in the angular dependence of the drag force. If the magnetic field is tilted from the dislocation axis by a small angle the electromagnetic interaction becomes unimportant and the drag force exhibits a peak which increases linearly with H.