Magnetic Domain Structures in CoCr Films Studied by Lorentz Microscopy

Abstract

The fast neutral injection method has proved to be a very efficient heating method either in open-ended configurations, or in toroidal configurations.Compared to other heating methods the fast neutral injection involves more technological difficulties, but less physical complexities. Furthermore these difficulties are met out of the plasma configuration and can be solved without stopping the confining machine. So it is quite natural in a paper devoted to fast neutral injection to divided it into two parts, the first part involves the production of the fast neutral beam, the second part involves the interaction of the neutrals with the plasma. But in these two parts, lots of atomic and molecular physics are needed and new phenomena can be currently discovered which will be emphasized in the second part.of our paper. But we will first consider the formation of the neutral beam which involves considerations on ion sources, acceleration and neutralization systems. In the second paper we wilI consider more the plasma physics.

The magnetic domain structure of CoCr layers studied by neutron depolarisation

“…A 1 MeV microscope has to be used for observing CoCr layers thicker than 0.1 pm, up to a maximum of 0.3 pm Iwasaki 1982, Grundy andAli 1983). A specially designed sample stage to exclude an external perpendicular field from the specimen during domain observations is essential Iwasaki 1982, Ohkoshi andKusuda 1983).Different domain configurations with in-plane magnetisation are observed in thin (<60 nm) CoCr layers (Grundy and Ali 1983, Ohkoshi and Kusuda 1983, Wielinga 1983. This can be explained by variations in the preparation methods.…”

“…Different domain configurations with in-plane magnetisation are observed in thin (<60 nm) CoCr layers (Grundy and Ali 1983, Ohkoshi and Kusuda 1983, Wielinga 1983. This can be explained by variations in the preparation methods.…”

“…For a good textured layer (Co77Cr23), with a thickness of 50 nm, stripe domains with a width of 0.1 pm were observed by Grundy and Ali (1983). Different domain forms were observed for films with much better orientation and a thickness of 0.1 pm (Grundy and Ali 1983, Ohkoshi and Kusuda 1983, Wielinga 1983. A magnetic black-and-white dot structure with a distance between the dots in the same order as the columnar diameter has been shown by Ohkoshi and Kusuda (1983).…”

“…Different domain forms were observed for films with much better orientation and a thickness of 0.1 pm (Grundy and Ali 1983, Ohkoshi and Kusuda 1983, Wielinga 1983. A magnetic black-and-white dot structure with a distance between the dots in the same order as the columnar diameter has been shown by Ohkoshi and Kusuda (1983). In this case the film morphology (one column consists of several crystallites) is totally different from the equiaxed crystal structure present in the layers of Grundy and Ali (1983) which show a stripe domain width in the order of the crystal size.…”

“…A 1 MeV microscope has to be used for observing CoCr layers thicker than 0.1 pm, up to a maximum of 0.3 pm Iwasaki 1982, Grundy andAli 1983). A specially designed sample stage to exclude an external perpendicular field from the specimen during domain observations is essential Iwasaki 1982, Ohkoshi andKusuda 1983).…”