INSITU MAGNETIZING EXPERIMENTS ON SMALL REGULARLY SHAPED PERMALLOY PARTICLES

The magnetisation process in small regular permalloy particles is investigated using the Foucault mode of Lorentz electron microscopy. Results are presented for particles of three different thicknesses, 17, 60 and 95 nm, with in-plane dimensions lying in the range 0.25 to 4.00-mu-m. From a study of Foucault images recorded under an applied field, hysteresis loops of individual particles are constructed. Examples of these are given together with a qualitative explanation of how the transition between solenoidal and non-solenoidal magnetisation distributions is dependent on particle dimensions.