SCANNING LORENTZ ELECTRON-MICROSCOPE WITH HIGH-RESOLUTION AND OBSERVATION OF BIT PROFILES RECORDED ON SPUTTERED LONGITUDINAL MEDIA

A transmission electron microscope operating with a cold field emissio n source has been modified to facilitate differential phase contrast m apping and applied to the observation of microscopic magnetic features appearing in recorded longitudinal media. After describing the design and performance of the scanning Lorentz electron microscope, as we ca ll it, results on the observation of bit patterns delineated on Co-bas ed sputtered longitudinal media are presented. Relations of observed b it profiles to macroscopic magnetic properties of media and to device performance are discussed. Then, magnetization fluctuation on a scale of magnetic crystallites constituting the medium is examined. Also giv en is an account of a stray field effect inherent in hard magnetic mat erials.