Accession Number : AD0285259

Title :   RESEARCH IN FERROMAGNETICS

Corporate Author : LABORATORY FOR ELECTRONICS INC BOSTON MASS

Report Date : 31 AUG 1961

Pagination or Media Count : 1

Abstract : Film geometry is related to wall motion, and it is shown that, for large films, the direction of the backgroty of motion. It was found that 750 domains could be recorded per inch of film. A description of another group of experiments performed to study anisotropy dispersion is also included. In the discussions of controlled domain-wall motion, nucleation and propagation of extraneous walls is indicated. The origin of these walls is investigated through a study of the magnetiznd magnetization affects this motion. In some cases it is found that a small transverse field increases the uniformity of motion. It was found that 750 domains could be recorded per inch of film. A description of another group of experiments performed to study anisotropy dispersion is also included. In the discussions of controlled domain-wall motion, nucleation and propagation of extraneous walls is indicated. The origin of these walls is investigated through a study of the magnetization distributions which can be expected in films. Four types of magnetization distributions at edges are considered: an Abrupt Edge configuration; a Tapered Edge configuration; a Curling configuration; and the Closure Domain configuration. A theoretical treatment of these configurations is given. Experimental results which support the theory are presented. Special projects required in the study of domain-wall-motion devices are described. Current sources for the tapered conductor are treated. Several improvements in the hysteresiscurve tracer, are discussed, as well as the adaptation of this curve tracer to Kerr-effect devices. An anomalous effect observed with an earlier curve tracer is also explained. (Author)

Descriptors :   *MEMORY DEVICES, *DATA STORAGE SYSTEMS, *FERROMAGNETIC MATERIALS, FERROMAGNETISM, HYSTERESIS, INSTRUMENTATION, MAGNETIC TAPE, MEASUREMENT, THICKNESS, THIN FILMS (STORAGE DEVICES)

Distribution Statement : APPROVED FOR PUBLIC RELEASE