A method for the preparation of aligned fibre samples for magnetic measurement using VSM

Ceramic vibrating sample magnenometer (VSM) samples are usually in the form of a sintered monolith, a sintered pressed pellet, or a powder set in a re sin or wax. The problem of mounting an aligned fibre sample, so that it ret ains alignment whilst remaining fixed in place as it is vibrated in a large magnetic held, was addressed for the first time. The most successful sampl e preparation method involved the formation of a flat, square composite sam ple through impregnation of the fibre with a fast-setting resin. Such align ed fibre samples had a fibre volume fraction of 3-4%, but random fibre samp les were also prepared, forming a much denser composite with typically 10 t imes as much fibre in the sample. The magnetic properties of a range of pol ycrystalline hexagonal ferrite fibres prepared by this method, and the effe cts of fibre alignment upon those properties, are currently being published in a series of articles. (C) 2000 Elsevier Science B.V. All rights reserve d.