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Method for Detection for Magnetic Contamination

IP.com Disclosure Number: IPCOM000037637D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Pesch, JA: AUTHOR

Abstract

The method described enables the detection of small magnetic particles. The necessary components for application of the method are a piece of magnetic recording medium, a magnet for magnetizing medium, an instrument for measuring the magnetic moment, and magnetic particles. The method depends upon the interaction of the magnetic fields of the particles with the magnetization of the magnetic medium. This interaction results in a decrease in magnetization of a previously magnetized magnetic medium when the particles are brought into proximity to the magnetic medium. This decrease in the magnetization of the medium is a measure of the field strength of the magnetic particles.

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Method for Detection for Magnetic Contamination

The method described enables the detection of small magnetic particles. The necessary components for application of the method are a piece of magnetic recording medium, a magnet for magnetizing medium, an instrument for measuring the magnetic moment, and magnetic particles. The method depends upon the interaction of the magnetic fields of the particles with the magnetization of the magnetic medium. This interaction results in a decrease in magnetization of a previously magnetized magnetic medium when the particles are brought into proximity to the magnetic medium. This decrease in the magnetization of the medium is a measure of the field strength of the magnetic particles.

As shown in Figs. 1, 2, and 3, a piece of magnetic recording medium 4 is initially in a demagnetized state indicated by the random arrows 5. The recording medium is then magnetized by an applied magnetic field, and the medium is uniformly magnetized as represented by the single long arrow 6. The magnetic moment of the magnetic medium, as shown in Fig. 2, is measured. Particles 7 are then applied to the surface of the magnetic medium. If some of the particles are magnetic, as indicated by the small arrows 8, the magnetic flux from the particles will interact with the magnetization in the medium as indicated by the shorter arrow 9 in the magnetic medium 4. Measurement of the magnetic moment of the magnetic medium is again performed. The decrease of...