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Abstract

We have studied the effect of stress induced anisotropy on domain wall dynamics in as-cast and annealed nanocrystalline Hitperm-type microwires. Annealing without stress leads to stress relaxation of the strong stresses frozen-in post the production process. Stress annealing at 300oC under 222.7 and 270.9 MPa, respectively, has triggered most complex domain wall dynamics.
Observed results are discussed considering that annealing under higher stresses leads to an enhancement of longitudinal (axial) anisotropy due to positive magnetostriction of both bcc-(Fe, Co) grain as well as the residual amorphous matrix, and subsequently due to the decreasing of axial anisotropy due to back stresses arising from the glass-coating after removing the mechanical load.
Magnetic anisotropies (axial and radial ones) after stress annealing can be responsible for the considerable influence of the annealing conditions on domain wall dynamics observed in Hitperm-type microwires. As a result of decreasing both anisotropies by different ways, the domain wall velocity decreased.