Low Temperature Physics: 39, 365 (2013); https://doi.org/10.1063/1.4801993 (5 pages)
Fizika Nizkikh Temperatur: Volume 39, Number 4 (April 2013), p. 469-474    ( to contents , go back )

The surface magnetic anisotropy of the CoFe2O4 nanoparticles with giant low-temperature hysteresis

K.A. Mozul’, L.P. Ol’khovik, Z.I. Sizova

V.N. Karazin National University, Kharkov 61077, Ukraine
E-mail: monk813@mail.ru

A.N. Bludov, V.O. Pashchenko

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine

V.N. Baumer, V.V. Vashchenko, M.A. Kolosov, A.P. Kryshtal', and M.F. Prodanov

Institute for Single Crystals of the National Academy of Sciences of Ukraine 60 Lenin Ave., Kharkov 61001, Ukraine

Received May 28, 2012, revised September 27, 2012

Abstract

The ferrimagnetic nanoparticles of CoFe2O4 of size 4–16 nm were synthesized by the pyrolysis of a Fe and Co acetylacetonates mixture. The field dependences of magnetization and hysteresis loops were investigated in magnetic fields up to 4000 kA/m at temperatures varied from 4.2 to 500 K. A considetable alternating contribution of “surface” anisotropy to the effective magnetic anisotropy of the nanoparticles was observed. It is found that there is a correlation between the magnetic properties that represent the specificity of small particles namely, between “surface” anisotropy, magnetization, high-field susceptibility.

PACS: 75.75.–c Magnetic properties of nanostructures;
PACS: 75.30.Gw Magnetic anisotropy;
PACS: 75.50.Gg Ferrimagnetics.

Key words: ferrimagnet, cobalt spinel, nanocrystal, technology, magnetic hysteresis, surface anisotropy.

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