Continual model of magnetic dynamics for antiferromagnetic particles in analyzing size effects on Morin transition in hematite nanoparticles

Alternative explanation to the effect of disappearance of the Morin transition on hematite nanoparticles with their size decreasing is proposed basing on an idea of the predominant role of the shape anisotropy for nanosize particles. Three types of the magnetic structure of hematite nanoparticles wi...

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Bibliographic Details
Published in:Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2018-05, Vol.20 (5), p.1-10, Article 141
Main Authors: Mishchenko, I., Chuev, M., Kubrin, S., Lastovina, T., Polyakov, V., Soldatov, A.
Format: Article
Language:English
Subjects:
Anisotropy
Antiferromagnetism
Axes (reference lines)
Basal plane
Characterization and Evaluation of Materials
Chemistry and Materials Science
Coexistence
Ferromagnetic phases
Ferromagnetism
Hematite
Inorganic Chemistry
Lasers
Magnetic structure
Materials Science
Mossbauer spectroscopy
Nanoparticles
Nanotechnology
Optical Devices
Optics
Photonics
Physical Chemistry
Research Paper
Size effects
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Summary:Alternative explanation to the effect of disappearance of the Morin transition on hematite nanoparticles with their size decreasing is proposed basing on an idea of the predominant role of the shape anisotropy for nanosize particles. Three types of the magnetic structure of hematite nanoparticles with various sizes are found by Mössbauer spectroscopy: coexistence of the well-pronounced antiferromagnetic and weakly ferromagnetic phases for particles with average diameters of about 55 nm, non-uniform distribution of the magnetization axes which concentrate on the vicinity of the basal plane (111) for prolonged particles with cross sections of about 20 nm, and uniform distribution of the easy axes in regard to the crystalline directions for 3-nm particles. Description of the temperature evolution of experimental data within novel model of the magnetic dynamics for antiferromagnetic particles which accounts the exchange, relativistic, and anisotropy interactions is provided, and the structural as well as energy characteristics of the studied systems are reconstructed.
ISSN:1388-0764
1572-896X
DOI:10.1007/s11051-018-4248-9