Size dependences of crystal structure and magnetic properties of DyMnO3 nanoparticles

We synthesized DyMnO3 nanoparticles with particle sizes of about 7.5a15.3 nm in the pores of mesoporous silica and investigated their crystal structure and magnetic properties. As the particle size decreased, the lattice constants of the DyMnO3 nanoparticles deviated from those of the bulk crystal,...

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Bibliographic Details
Published in:Journal of magnetism and magnetic materials 2013-11, Vol.345, p.288-293
Main Authors: TAJIRI, T, TERASHITA, N, HAMAMOTO, K, DEGUCHI, H, MITO, M, MORIMOTO, Y, KONISHI, K, KOHNO, A
Format: Article
Language:English
Subjects:
Coercive force
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Condensed matter: structure, mechanical and thermal properties
Crystal structure
Diamagnetism, paramagnetism and superparamagnetism
Distortion
Exact sciences and technology
Lattice parameters
Lattice strain
Magnetic properties
Magnetic properties and materials
Magnetic properties of nanostructures
Nanoparticles
Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals
Particle size
Physics
Structure of solids and liquids
crystallography
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Summary:We synthesized DyMnO3 nanoparticles with particle sizes of about 7.5a15.3 nm in the pores of mesoporous silica and investigated their crystal structure and magnetic properties. As the particle size decreased, the lattice constants of the DyMnO3 nanoparticles deviated from those of the bulk crystal, and the JahnaTeller distortion in the nanoparticle systems decreased. In addition, the estimated lattice strain increased with decreasing particle size. The DyMnO3 nanoparticles showed superparamagnetic behavior. The blocking temperature and the coercive field increased with decreasing particle size, and this behavior was contrary to the usual magnetic size effects. It is deduced that these unique size dependences of the magnetic properties for the DyMnO3 nanoparticles were derived from the changes in lattice constants and lattice strain. The anisotropic lattice deformation in the crystal structure of the nanoparticles induces an enhancement of the magnetic anisotropy, which results in the increase in blocking temperature and coercive field with decreasing particle size.
ISSN:0304-8853
DOI:10.1016/j.jmmm.2013.06.055