A new method is developed using a transparent indicator ferrimagnetic magneto‐optic film with in‐plane anisotropy for visualization and direct experimental study of dynamic magnetization processes and nondestructive characterization of the defect structure of magnetic multilayers. Some examples of its application to the investigation of peculiarities of the as‐grown magnetic structure of electrochemically produced CoNiCu/Cu multilayers with a giant magnetoresistance (GMR) effect and magnetization reversal by domain wall motion are described. ©1995 American Institute of Physics.