ACCOMMODATION OF THE SPEED DISTRIBUTION OF MAGNETIC DOMAIN-WALLS TO THEIR EDDY-CURRENT INTERACTIONS

The eddy interaction of Pry & Bean type domain walls, distributed randomly across a lamination, is investigated by Monte Carlo simulation supported, for large mean domain width/lamination thickness ratio W/D, by analysis. When all walls are constrained to make equal flux rate contributions, the eddy loss exceeds the "classical" (uniform dB/dt) loss Λc by a factor ηR = ηO + 1 where ηO = 1.628W/D is the corresponding factor without eddy overlap. This confirms earlier work. Howe ver, when each wall adjusts its rate to balance eddy drag and applied field pressure, a lower ratio ηA = ηO + ΔηA results with 0.7 < ΔηA < 1. This is contrary to Bertotti's rule that independent random eddy interactions contribute Λc while correlated interactions make a higher contribution. © 1990.