In order to find out the magnetization configurations in the platehyphen;shaped fine particles of hcp colbalt, the energy densities of the particle with various magnetization configurations are calculated as a function of the particle radiusr0for the axial rationfrom 1 to 1/8. It is found that the particle has a single domain structure ifr0is smaller than the critical radiusrc, and thatrcis 17 nm forn=1/2, 12 nm forn=1/4, and 11 nm forn=1/8. It is also found that the particle withr0larger thanrchas a form of the curling configuration: the spins stand up in the center of the particle, but become the circular configuration in the offhyphen;center region, and that the particle has this curling configuration tor0of 33 nm forn=1/2 and 200 nm forn=1/4.
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