The issue 7 of the international electronic scientific journal Natural Science Review has been published, the founder and publisher of which is the Joint Institute for Nuclear Research. In the new issue, readers can learn about the review article "Structural, magnetic states and pressure-induced phenomena in complex nanoscale magnetic oxides" by a group of authors from FLNP (D. P. Kozlenko, N. M. Belozerova, S. E. Kichanov, E. V. Lukin, O. N. Lis, A. V. Rutkauskas, B. N. Savenko), Institute of Physics of the Academy of Sciences of the Czech Republic (J. Iraq), National Research Centre of the National Academy of Sciences of Belarus for Materials Science (G. S. Rimsky, A. L. Zheludkevich), Dui Tan University, Vietnam (N. T. Dang).
The results of the recent investigations of the crystal and magnetic structure of complex nanosized oxides of manganese and iron in a wide range of temperatures and pressures are presented in the article. The use of the advanced techniques of neutron and X-ray diffraction together with complementary methodologies allowed the authors to identify completely new properties of the studied nanoscale systems, significantly different from the characteristics of bulk materials. In particular, in nanostructured manganites, the nanoparticles containing a ferromagnetic (FM) core and an antiferromagnetic (AFM) shell were discovered.
The high-pressure effect enables controlling their magnetic properties by reducing the volume fraction of the FM core and increasing the volume fraction of the AFM shell. In the nanostructured CoFe2O4 ferrite, the saturation magnetization increased as the size of nanoparticles decreased from 330 to 12 nm using mechanical grinding, related to the redistribution of cobalt ions between various crystallographic positions. In the nanostructured cation-deficient Zn0.34Fe2.53O4 ferrite, the formation of a relatively large uncompensated ordered magnetic moment in the low temperature was observed, significantly exceeding the values for bulk analogues. A pressure-induced structural phase transition from the cubic spinel structure to the orthorhombic post-spinel structure was also observed in both compounds. The results obtained not only deepen the fundamental understanding of the microscopic mechanisms that estimate the relationship between physical properties and structural features of oxide magnetic nanomaterials but they can also be in demand when developing promising materials for electronics, medicine and current data storage systems.
The key results of the research were obtained using the DN-6 and DN-12 neutron diffractometers of the IBR-2 pulsed reactor that provide broad possibilities for an in-depth investigation of both the atomic and magnetic structure of functional materials. JINR laboratory equipment was also used. The investigation was the result of fruitful international cooperation, uniting the unique experience of scientists from JINR, as well as from the research centres in Belarus, the Czech Republic and Vietnam.
Autor Lis Olga
Translator Voskanyan Elena