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Information × Registration Number 0201U003663, 0100U003285 , R & D reports Title Investigation of nature and formation mechanism of magnetic properties of high anisotropic ferrimagnet macro- and nanocrystals popup.stage_title Head Popkov Yu.A., Registration Date 03-04-2001 Organization Kharkov National University named after V.N. Karazin popup.description2 Subject of inquiry is hexagonal ferrites of M type as natural monocrystals and those enriched with the 57Fe isotope as well as fine powders. The goal of the work at the first stage is determination of low-temperature changes of the magnetostriction anisotropy constants in crystals enriched with the 57Fe isotope and determination of the thickness of the structure-defective near-surface region with a disturbed magnetic structure on a monocrystal. Methods of investigation are static and resonance. Magnetostriction deformation are measured in the basal plane of monocrystals. The magnetostriction constant lambda is found. The temperature dependence of the sublattice magnetizations, the sublattice contributions of Fe3+ ions in sites 12k and resulting contribution of ferrum ions of the remained sites into the constant lambda at low temperatures are obtained by the NMR method. This contributions are shown to have different signs and the main contributions is from ions in 12k sites. With the use of the NGR spec troscopy method it is found that in the highly anisotropic ferrites the thickness of the near-surface layer, where magnetic moments of ferrum ions depart from the hexagonal axis, is of 3 nm. From these data and from magnetic measurement results the degree of nonuniformity of microcrystal magnetic structure is esstimated. Product Description popup.authors popup.nrat_date 2020-04-02 Close