Magnetic force microscopy study of dense stripe domains in Fe-B/Co-Si-B multilayers and the evolution under an external applied field

The effect of the permanent compression acting on multilayered Fe-B/Co-Si-B thin films has been studied by using magnetic force microscopy (MFM). Sinc e both materials exhibit positive and negative saturation magnetostriction, respectively, the magnetic-moment distribution and thus the domain structu re of these multilayers are strongly dependent on the thickness of each lay er. Different MFM contrast levels and domain sizes have been measured in st ressed and unstressed multilayers with various Fe-B and Co-Si-B layer thick ness. Both kinds of samples, stressed and unstressed thin films, present a weak perpendicular anisotropy. For identical composition of the multilayers , an increase of the magnetization component perpendicular to the sample pl ane has been observed in stressed samples compared to their unstressed coun terparts. In addition, the effect of the stress on the magnetization proces s has been studied by analyzing the evolution of the domain structure with an externally applied magnetic field in MFM imaging.