Title :
Chromium dioxide particles for magnetic recording
Author :
Auweter, H. ; Feser, R. ; Jakusch, H. ; Müller, M.W. ; Muller, N. ; Schwab, E. ; Veitch, R.J.
Author_Institution :
BASF AG, Ludwigshafen, West Germany
fDate :
1/1/1990 12:00:00 AM
Abstract :
Chromium dioxide was introduced in the later 1960s as the first magnetic material capable of high density recording. Since that time a continuous improvement of material properties has been made possible. The most recent improvement concerns particles with coercivities well above 70 kA/m which can be prepared by a modified hydrothermal process without using expensive Ir doping. Although CrO2 has a somewhat higher specific magnetization, the static magnetic properties of CrO2 and cobalt-modified iron oxides are comparable. There are, however, some significant differences in recording performance. CrO 2 pigments show better print-through to noise ratios than Co-modified iron oxides of the same mean magnetic volume. There are no problems with erasability, which becomes increasingly difficult to control for high-coercivity cobalt-modified iron oxides. Finally, CrO 2 is the only pigment material which allows thermomagnetic duplication
Keywords :
chromium compounds; coercive force; ferromagnetic properties of substances; magnetic properties of fine particles; magnetic recording; magnetisation; powder technology; thermomagnetic recording; CrO2 particles; coercivities; erasability; high density recording; magnetic recording; modified hydrothermal process; pigment material; print-through to noise ratios; recording performance; static magnetic properties; thermomagnetic duplication; Chromium; Coercive force; Continuous improvement; Doping; Iron; Magnetic materials; Magnetic recording; Magnetization; Material properties; Pigments;
Journal_Title :
Magnetics, IEEE Transactions on