SPATIAL FLUCTUATIONS OF MAGNETOSTRICTION IN A NANOSTRUCTURED SYSTEM

The elongation induced by magnetizing along the longitudinal direction a nanocrystalline ribbon has been measured as a function of the trans verse applied field. For very low transverse fields the total elongati on is negative whereas it shifts to positive values for increasing tra nsverse applied fields. This behavior can be explained as a consequenc e of spatial fluctuations of the average magnetostriction. It is shown that such fluctuations should be correlated in length to the domain w idth. The possible origin of the magnetostriction fluctuation as eithe r anisotropic average of the local magnetostriction - in the range of the exchange correlation length and thereby in the domain - or spatial fluctuations of the crystallized fraction, is indicated. (C) 1998 Els evier Science B.V. All rights reserved.