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Magnetic Contrast Analyzer

IP.com Disclosure Number: IPCOM000090816D
Original Publication Date: 1969-Jul-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Wardly, GA: AUTHOR

Abstract

Magnetic field measurement is effected by a magnetic contrast analyzer in the scanning electron microscope. An indication of magnetic field strength near a change in magnetization of a specimen under magnetic contrast observation in the scanning electron microscope is provided by the axial shift in the apparent location of the magnetization change when viewed, illuminated, by two diametrically opposed collection apertures. The shift occurs along the axis of magnetization and the apertures lie a distance from the scanning area but essentially on-axis. The shift is the result of a combined effect.

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Magnetic Contrast Analyzer

Magnetic field measurement is effected by a magnetic contrast analyzer in the scanning electron microscope. An indication of magnetic field strength near a change in magnetization of a specimen under magnetic contrast observation in the scanning electron microscope is provided by the axial shift in the apparent location of the magnetization change when viewed, illuminated, by two diametrically opposed collection apertures. The shift occurs along the axis of magnetization and the apertures lie a distance from the scanning area but essentially on-axis. The shift is the result of a combined effect. Secondary electrons leave the axial edge of the fringe field before attaining a full deflection when travelling toward one aperture while, when travelling toward the other, the electrons can enter deflecting fields which are not characteristic of their point of origin. The latter effect can be deleted on geometric considerations. The former effect is a function of the field strength and its radial extent. The relationship can be expressed as (L/a(f))/2/ = 6.7 x the square root of V(s)/ the absolute value of B(f)a(a) -1 where L is the apparent field dependent shift in cm., a(f) is the effective flux extent. B(f) is the effective flux density in gauss, and V(s) is the secondary electron energy selected for collection in e.v. A second method of field measurement involves the measurable and distinct shortening or elongation of shadows cast by nonmag...