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Information × Registration Number 0200U003583, 0197U002499 , R & D reports Title Investigation of magnetic state of the fine ferrite systems with particle sizes close to the critical value popup.stage_title Head Popkov Yu., Registration Date 08-06-2000 Organization Kharkov National University named after V.N. Karazin popup.description2 Subject of inquiry is a hexagonal barium ferrite with the systems of nano- and microcrystals as unsubstituted magnetic matrix. The goal of the work is to investigate the dependence on temperature, magnetic field and dispersivity of the magnetic state of the barium ferrite powder which is used as a base material to develop the biasing and recording media. The methods of investigation used are static and resonant magnetic measurements and electron macroscopy. The magnetic state of the system of the highly anisotropic nanocrystals with a volume near the critical value which are obtained by using a cryochemical technology is investigated. The (H-T) diagram is obtained in the range of 4,2-723 K, where a number of regions of states not characteristic of macroscopical object has been localized. A region of the magnetostable (superparamagnetic) state (390-723 K) is found, which is to be accounted for when ferrite powders are used as service materials. A nontypical field dependence of magnetization, which refl ects a complicated character of magnetization processes in rather large but yet single-domain particles has been found on the system of microcrystals in the whole temperature range. The results of this work obtained on the model system of particles with a large specific surface can serve as a base for further studies aiming to solve the surface magnetism problems. Product Description popup.authors popup.nrat_date 2020-04-03 Close