Magnetic force microscopy image of Co–Cr–Ta layer in perpendicular magnetic tape at high linear recording density

Abstract

In this study, magnetic force microscopy (MFM) was used to investigate the recording capability of a perpendicular magnetic tape at a higher linear recording density. Perpendicular magnetic tapes with polyimide base sheets 10 μm thick were fabricated by a facing-target sputtering system [H. Yoshimoto, K. Kuga, Y. Yoneda, and J. Numazawa, J. Magn. Magn. Mater. 148, 357 (1995)]. A Co–Cr–Ta (200 nm) monolayered tape with a base sheet of excellent surface roughness was fabricated. A complete recorded bit pattern of 250 kfci was observed as a MFM image on the tape. A recorded bit pattern of 300 kfci was also observed. A Co–Cr–Ta/Ni–Fe (150/50 nm) multilayered tape was also fabricated. The remnant magnetization state on this tape at 50 kfci was improved by the presence of an underlayer (Ni–Fe) only 50 nm thick. The MFM image at 250 kfci was the same as with a monolayered tape.