3rd-8th September, 2017: The International Conference on the Applications of the Mössbauer Effect, St.Petersburg, Russia

[Z. Klencsar]

The International Conference on the Applications of the Mössbauer Effect (ICAME-2017) was held during the days of September 03-08, 2017, in St.Petersburg, Russia. On the conference Sándor Stichleutner presented a poster dealing with results obtained among others by the means of Mössbauer spectrometry in connection with magnetite/maghemite nanoparticle samples. The corresponding abstract can be read below, whereas the presented poster can be downloaded from http://esr.hu/plantnano/posters/2017_ic ... netite.pdf

The effect of preparation conditions on magnetite nanoparticles obtained via chemical co-precipitation

Klencsár Z. 1, Ábrahám A. 2,3, Szabó L. 3, Szabó E.Gy. 3, Stichleutner S. 1, Kuzmann E. 2, Homonnay Z. 2, Tolnai Gy. 3,4

1 - Nuclear Analysis and Radiography Department, Centre for Energy Research, Hungarian Academy of Sciences, 1121 Budapest, Hungary
2 - Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary
3 - Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary
4 - Fehérvári út 168., 1116 Budapest, Hungary

On account of their advantageous material properties, such as a high Curie-temperature, high levels of magnetization, high specific surface area, superparamagnetism along with chemical stability, low toxicity and good biocompatibility under physiological conditions, magnetite nanoparticles are found to be exceedingly useful in various applications in fields such as catalysis [1], biomedical diagnostic and therapeutic applications [2] as well as environmental remediation [3]. However, when prepared in the form of nanoparticles, in corresponding 57Fe Mössbauer spectra magnetite often presents itself in a way that deviates considerably from that of its bulk counterpart [4,5], which can make its identification dubious, especially solely on the basis of spectra recorded at room temperature. Formation of magnetite-maghemite core-shell structure, magnetic relaxation phenomena as well as non-stoichiometric compositions [4,5] may lead to such deviations, and the particles may also lack long-term stability due to aging via oxidation [6]. In the frame of the present work we contribute to this subject by investigating magnetite nanoparticle samples prepared via chemical co-precipitation by applying different conditions regarding the ambient atmosphere, the presence of a surfactant coating agent (malic acid) and the final drying temperature. We access the effects of preparation conditions on properties of the resulting nanomaterial by the use of powder X-ray diffractometry, transmission electron microscopy, 57Fe Mossbauer spectroscopy and ferromagnetic resonance spectroscopy, and make an attempt to paint a consistent picture of the observed differences in material properties.

Acknowledgements
This work was supported by the Hungarian National Research, Development and Innovation Office – NKFIH (K115784 and K115913). Technical help of Mrs. Lászlóné Millián is gratefully acknowledged.

References
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