Control of magnetic properties of complex oxide systems

Denis Vinnik, Doctor of Chemical Sciences, Professor, Head of the Department of Materials Science and Physical Chemistry of Materials, Director of the Research Institute for Advanced Materials and Resource Saving Technologies at SUSU. Credit: SUSU

The study of complex iron oxides to create new functional materials is one of the most intensive areas of research for SUSU scientists. The physical properties of complex iron oxide systems can change by changing the chemical composition. This allows you to monitor the basic effects that occur when ions are replaced. In a new study, researchers decided to investigate ferrites structured with spinel, changing their magnetic properties by changing their chemical composition by replacing iron ions. The results of their research were published in Nanomaterials.

The researchers, an international group that includes scientists from SUSU and their colleagues from Belarus, Saudi Arabia and India, examined the ferrites of the Co-Ni system with double substitution of iron ions with thulium and terbium ions. Chemists were interested in the magnetic properties of the test compounds that manifest in ferrites during the transition to the nanoscale.

During the study, the scientists determined the peculiarities of the distribution of substituted ions in the structure of ferrite spinel. The relevance of the study arose due to the correlation between the distribution of substituent ions in ferrite spinel and its influence on magnetic properties under conditions of double substitution of iron ions with Tm and Tb ions comparable in radius.

“The samples were synthesized by the sol-gel method, which allows the formation of complex oxides of nanoscale. However, ultrasonic assistance was applied during the synthesis, which allowed us a more homogeneous distribution of replacement ions and a reduction in average crystalite size,” said SUSU chemist Dr. Denis Vinnik.

The synthesis was performed by scientists from Saudi Arabia. The study of microstructural parameters and magnetic properties of nanoscale ferrite spinels was conducted at the Research and Education Center for Nanotechnology SUSU. As a result, experts have identified an interesting property of the studied oxides: By increasing the degree of substitution of iron ions by ions with large radii, the unit cell parameter decreased, although theoretically it should have increased.

“We suggested that this anomaly could be the result of a surface compression effect of nanocrystallites. Thus, a decrease in crystal size as a result of substitution with Tm and Tb ions led to an increase in surface layer content. This, as we know, can lead to surface compression effects in nanoscale crystallites , and as a consequence, the deformation of a single cell, “said Aleksey Trukhanov, a senior researcher at the SUSU Center for Research and Education in Nanotechnology.

For now, the studies are theoretical, but they can be used as a basis for completing further studies of the synthesis of compounds of complex iron oxides and the correction of their properties. The scientists’ plans include studying the functional properties of ferrite spinels in the absorption of electromagnetic radiation.

Scientists have noted that chemical compounds can be used in electronics to create sensors, as well as in biomedicine for targeted drug delivery or contrast visualization.

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More information:
Munirah A. Almessiere et al. Influence of Tm3 + and Tb3 + cation substitution on the structure and magnetic parameters of ferrite Co-Ni Nanospinel, Nanomaterials (2020). DOI: 10.3390 / nano10122384

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Citation: Control of magnetic properties of complex oxide systems (2020, December 24) taken on December 24, 2020 from

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