Detailed measurements of slow magnetization processes in tape-wound cores

The technology based on the saturable-core reactor, including magnetic amplifiers and other nonlinear magnetic devices,1 has grown rapidly in the past decade. This has stimulated development of commercially available polycrystalline magnetic materials, and prompted several studies of their properties going well beyond the mere collection of empirical, macroscopic data. A recent paper,2 an attempt to summarize the state of the art from the electrical engineering standpoint, indicated how changes in the magnetic state of a tape-wound core may take place. A lengthy bibliography included papers on the structure and arrangement of domain walls in tapes, calculations of their growth and propagation energies, and several papers showing microscopic domain patterns in isolated samples.