Accession Number:

AD0817305

Title:

MAGNETIC AND DIELECTRIC LOSS IN MAGNETIC INSULATORS.

Descriptive Note:

Summary technical rept. 1 Jan-31 Dec 66,

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE MICROWAVE AND QUANTUM MAGNETICS GROUP

Personal Author(s):

Report Date:

1967-06-01

Pagination or Media Count:

89.0

Abstract:

Domain-wall motion in single crystals of silicon doped YIG has been studied over the temperature range 4.2-300 K. Samples were cut in the form of picture frames to obtain a simple domain configuration having magnetic properties essentially determined by a single moveable wall. The existence of the desired domain structure has been reasonably well established by domain-pattern observations and from certain characteristic features of the switching pulse. The temperature dependence of the switching behavior, in doped samples, does not agree with the valence-exchange model. The inverse mobility proportional to the wall damping parameter shows a temperature dependence similar to that of the linewidth for microwave resonance, suggesting that the two loss processes are related. It is argued that the low temperature losses, in both cases, are due to Fe2 acting as a localized relaxer. Despite the apparent absence of valence-exchange in our wall switching measurements, the mechanism does appear to be responsible for the temperature activated domain-wall relaxation seen in the initial permeability spectrum. Reasons for this discrepancy are discussed. The microwave linewidth of several silicon doped samples has been measured at K sub u band between room temperature and the Curie point.

Subject Categories:

  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE