AS-DEPOSITED CRYSTALLINE BARIUM FERRITE THIN-FILM MEDIA FOR LONGITUDINAL RECORDING

Using facing target sputtering, crystalline barium ferrite (BaFe12O19, BaM) has been deposited onto a silicon nitride coated carbon substrat e, producing high-quality, randomly oriented crystalline films in-situ at a substrate temperature of 640 degrees C without post-deposition a nnealing. Using inductive read-write heads, longitudinal recording tes ts reveal that randomly oriented BaM thin films have a linear recordin g density (D-50) greater than 100 kfci and a high signal to noise rati o (similar to 39 dB). The low noise performance of BaM thin film is co nsistent with its measured small and negative Delta M value, indicatin g no intergranular exchange interaction. It is argued that BaM is intr insically a low-noise medium with exchange decoupled grains, regardles s of how the grains are oriented and how dense the sputtered films are .