Browse Prior Art Database

Determination of Saturation Magnetization by a Dynamic Mechanical Method

IP.com Disclosure Number: IPCOM000077829D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 18K

Publishing Venue

IBM

Related People

Berry, BS: AUTHOR [+2]

Abstract

An effect in the flexural vibration behavior of thin reeds of ferro-magnetic materials, enables measurement of their saturation magnetization.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 68% of the total text.

Page 1 of 2

Determination of Saturation Magnetization by a Dynamic Mechanical Method

An effect in the flexural vibration behavior of thin reeds of ferro-magnetic materials, enables measurement of their saturation magnetization.

A reed is mounted as a cantilever with provision for excitation and detection of the flexural modes of vibration, e.g., via electrostatic transducers. With the specimen first subject to a strong enough field to produce the saturation magnetization I(s), the effect consists of an increase in the resonant frequencies with further increase in the applied field. The origin of this effect is the magnetic restoring couple, which acts to return the reed to a straight undeflected shape parallel to the field direction. This action contributes to the overall storing constant of the reed and thereby increases the resonant frequencies.

Theoretically, the effect is present at all tones of vibration.

The sensitivity decreases very greatly for the higher overtones, since the much larger elastic spring constant associated with these more curvaceous shapes makes the magnetic effect correspondingly smaller. Consequently, attention is restricted to the fundamental mode. For this case, the variation in the frequency f with field H is given approximately by:

(Image Omitted)

H(s) is the minimum field to produce saturation, f(s) is the frequency at H(s), I(s) is the saturation magnetization and E(s) is Youngs modulus at saturation. In addition, l is the length and d is the...