Patent · US Expired

Magnetic recording medium

US6040041A · kind A · utility

1Cited by

21References

6Claims

0Family size

Assignee

Emtec Magnetics GmbH · DE

Inventors

Klaus-Dieter Götz · Sersheim, DE
Helmut Jakusch · Bischofswerda, DE
Werner Loch · Erpolzheim, DE
Erich Hoffmann · Heidelberg, DE
Hans-Georg Gottmann · Hersbruck, DE
Hans-Joachim Jenor · Hersbruck, DE
Johann Voit · Gilching, DE

Key dates

Filing date	Feb 12, 1998
Grant date	Mar 21, 2000
Priority date	—
Expiry date	Feb 12, 2018

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10T428/257
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A magnetic recording medium consisting of a nonmagnetic substrate and at least two magnetizable layers which are applied thereon and contain metal oxides as magnetic pigment is described, the pigment of the upper layer having a higher BET value than that in the lower layer. According to the invention, the upper layer has a thickness in the range of 3-5 .mu.m when dry and the lower layer a thickness in the range of 1.1-3 .mu.m when dry. Particularly advantageous results are obtained when the magnetic pigment of the upper layer is cobalt-doped .gamma.--Fe.sub.2 O.sub.3 and that of the lower layer is acicular CrO.sub.2. With the double-layer recording medium obtained according to the invention, in particular the output level at low frequencies is improved without the frequency curve showing the usual depression in the middle.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.