A technique for simulating the effect of long-term magnetic viscosity in permanent magnets

P.J. Thompson, Robert Street

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

A technique is presented by which the change in magnetisation at a constant field as a result of long-term magnetic viscosity can be estimated. When an alternating field with an initial amplitude Delta H is superposed upon a bias field H and gradually decreased to zero, a change in the magnetisation at H will result. Utilising Neel's description of magnetic viscosity, in which magnetisation changes are formulated in terms of an effective viscosity field, h(f)(t), superposed on the applied field, we calculate the equivalent waiting time, t, required for h(f)(t) to attain a value equal to Delta H. We propose that the calculated time interval t represents the waiting time at the field H required for viscosity effects to bring about the equivalent change in magnetisation. If the working point of a permanent magnet or magnetic recording medium is known, this technique provides a quantitative estimate of the long-term stability of the magnetic state of the material.
Original languageEnglish
Pages (from-to)163-169
JournalJournal of Magnetism and Magnetic Materials
Volume171
DOIs
Publication statusPublished - 1997

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