Accession Number : AD0623611

Title :   MAGNETIC MEASUREMENTS WITH LORENTZ MICROSCOPY,

Corporate Author : MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB

Personal Author(s) : Cohen,M. S.

Report Date : 19 MAR 1965

Pagination or Media Count : 12

Abstract : Lorentz microscopy is a powerful technique for investigating thin NiFe films because it offers high resolution, because it provides an unequivocal identification of the local magnetization direction, and because it permits correlations to be made between the magnetic structure and the underlying physical (crystallographic) structure of the film. The following measurements are discussed: (1) determination of the Curie temperature; (2) measurement of the anisotropy field H sub K by the standard hysteresigraph and the Feldtkeller techniques; (3) quantitative studies of wall motion by labyrinth propagation and by wall creep; (4) the investigation of anisotropy dispersion by the Crowther and Torok techniques. The accuracy of these measurements is, in general, lower than that of the analogous measurements made by macroscopic methods on films deposited on glass substrates. Nevertheless, macroscopic measurements performed on a film on a glass substrate showed good agreement with Lorentz measurements performed on a simultaneously-deposited film which was suitable for Lorentz microscopy.

Descriptors :   (*METAL FILMS, MAGNETIC PROPERTIES), (*ELECTRON MICROSCOPY, METAL FILMS), NICKEL ALLOYS, IRON ALLOYS, ANISOTROPY, CREEP, TRANSITION TEMPERATURE

Distribution Statement : APPROVED FOR PUBLIC RELEASE