Abstract: A process and apparatus for producing magnetic discs in which the preferred direction of orientation of the anisotropic magnetic particles, contained in an organic binder system, is tangential to the circumference of the disc. Orientation is effected, prior to solidification of the magnetic layer, by the action of a magnetic field which is formed in the plane of symmetry between at least two pairs of magnetic poles, the poles of each pair being of the same polarity and opposite each other. One pair of poles flares out in cross section toward the plane of symmetry between the pairs of poles, whereas the other pair or pairs of poles of opposite polarity, when viewed in cross section, taper toward the said plane of symmetry to a point, the distance between the poles of such pair(s) being greater than that between the flared poles, and the plane of symmetry of the pairs of poles being in the plane of the disc.

Abstract: The invention concerns a device for the non-destructive measurement of the remanent flux density of magnetic recording media, by recording a specific signal and reproducing the recorded signal by means of two pairs of magnetic recording and playback heads arranged opposite one another and perpendicular to the plane of the recording medium, the ratio of the distance between the individual magnetic heads of each pair of heads to the wavelength of the recorded signal being within a specific range, and the said distance being such that a magnetic recording medium is movable symmetrically between the pair of heads, a common measuring unit being associated with the playback pair. Further features of the device relate to the design of the magnetic recording and playback heads, the measuring unit and the rate at which the particular magnetic recording medium being tested moves between the pairs of heads.