Accession Number : AD0468085

Title :   THE DETECTION OF WEAK MAGNETIC FIELDS USING DIPOLE RESONANCE IN THIN-PERMALLOY FILMS,

Corporate Author : CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB

Personal Author(s) : Frank, C. E.

Report Date : 18 JAN 1965

Pagination or Media Count : 91

Abstract : Anisotropic magnetic thin films can be formed by vacuum evaporation and deposition of ferromagnetic materials in a dc magnetic field parallel to the substrate. Such films, especially those of nickel-iron of permalloy composition, were extensively studied, primarily with respect to properties useful in digital computer applications. Interest in those devices has developed for detecting very weak magnetic fields, using low-frequency-switching methods as described by West, Odom, Rice, and Penn. The work reported uses a new ultra-high-frequency magnetic-spinresonance method devised by the author. Among new results obtained are analytical and experimental verifications of the high sensitivity attainable. Although the actual sensitivities measured in ordinary laboratory surroundings were limited to approximately ten microgauss by the ambient magnetic noise level, the system is capable of much greater sensitivity if used in quieter locations. (Author)

Descriptors :   (*FERROMAGNETIC MATERIALS, MAGNETIC FIELDS), (*MAGNETIC FIELDS, DETECTION), ANISOTROPY, NICKEL ALLOYS, IRON ALLOYS, PERMEABILITY(MAGNETIC), MAPPING, MEASUREMENT.

Distribution Statement : APPROVED FOR PUBLIC RELEASE