Energy Dissipation in Square Loop Ferromagnetic Materials with Specific Application to Switch Cores

Abstract

A determination is made of the energy dissipation in a square loop ferromagnetic material due to domain wall motion. These energy losses are separated into three terms, representing the relaxation loss. The order of magnitude of the energy loss per cycle is found for an F-262 ferrite and a 140 wrap 4-79 molybdenum permalloy core. From the values thus determined, the power loss of these cores is calculated for a frequency of 100 kilocycles, assuming a semi-infinite step function input. The calculated order of magnitude is in agreement with the experimental results for a ferrite; no data is available for the metallic cores. The results indicate that external cooling will be needed for switch core matrices operated at this frequency. A number of reasons are given to show that metallic cores should be preferable to ferrites as switch cores.