Automated spatial filter station for bubble film characterization

A fully automated spatial filter station for bubble film static characterizations is described. The spatial filter is used to measure the diffraction angles of a laser beam transmitted through the bubble film under measurement. The demagnetized domain stripe width is calculated from the first-order diffraction angle for the bubble film under zero bias field, and the saturation magnetization is derived from the bias field which induces a domain periodicity corresponding to a certain value of magnetization in the film. The whole measurement process has been automated, which takes about one minute per wafer, with a precision for domain stripe width better than 0.5 percent and that for saturation magnetization 1 percent.