Recording performances of Ba-ferrite coated perpendicular magnetic tapes

Abstract

Barium-ferrite fine-particle-coated perpendicular magnetic recording tapes have been experimentally fabricated. Typical tapes have M <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> = 120 - 130 emu/cc, H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf> = 600 - 1500 Oe and perpendicular squareness ratio <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M_{r\perp}/M_{s}</tex> larger than 0.9. Tape recording performances were measured with a perpendicular head as well as With a ring-shaped head. A good short wavelength response, D <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</inf> = 76k FRPI, which has never been attained by longitudinally oriented particulate tapes, was obtained; The relationship between perpendicular squareness ratio and output was also investigated to show the importance of perpendicular orientation for attaining a higher recording density.