The effects of barium ferrite particles added to VHS tapes

The effects of Barium ferrite particles added to VHS tapes were investigated. The amount of Barium ferrite particles added was from 0 to 20 weight percent of acicular magnetic particles. As the amount of Barium ferrite particles was increased, both squareness ratio and coercive force in perpendicular direction of the tape increased, so that the characteristics of perpendicular recording appeared. When the amount of Barium ferrite particles increased, output in the high frequency area (e.g. output of Frequency Modulated signal) became higher, but at the same time, the smoothness of the tape surface became slightly degraded. To improve the surface smoothness, we set the smoothing process next to the longitudinal magnetic orientation process. The tapes with Barium ferrite particles added from 5 to 10 weight percent showed 0.5dB increase both luminance signal to noise ratio and chrominance signal to noise ratio compared to the tape with no Barium ferrite particles.