Ferrimagnetic nanoparticles are used in biotechnology (as drug carriers, biosensors, elements of diagnostic sets, contrast agents for magnetic resonance imaging), catalysis, electronics, and for the production of magnetic fluids and magnetorheological suspensions, etc. The use of magnetic nanoparticles requires enhanced magnetic characteristics, in particular, high saturation magnetisation.The aim of our study was to obtain single-phased magnetic nanoparticles of MnxFe3–xO4 solid solutions at room temperature. We also studied the dependence of the changes in their structure, morphology, and magnetic properties on the degree of substitution in order to determine the range of the compounds with the highest magnetisation value.A number of powders of Mn-substituted magnetite MnxFe3–xO4 (x = 0 – 1.8) were synthesized by means of co-precipitation from aqueous solutions of salts. The structural and micro-structural features and magnetic properties of the powders were studied using magnetic analysis, X-ray diffraction, transmission electron microscopy, and IR spectroscopy.The X-ray phase analysis and IR spectroscopy confirm the formation of single-phase compounds with cubic spinel structures. The maximum increase in saturation magnetization as compared to non-substituted magnetite was observed for Mn0.3Fe2.7O4 (Ms = 68 A·m2·kg–1 at 300 K and Ms = 85 A·m2·kg–1 at 5 K). This is associated with the changes in the cation distribution between the tetrahedral and octahedral cites.A method to control the magnetic properties of magnetite by the partial replacement of iron ions in the magnetite structure with manganese has been proposed in the paper. The study demonstrated that it is possible to change the magnetisation and coercivity of powders by changing the degree of substitution. The maximum magnetisation corresponds to the powder Mn0.3Fe2.7O4. The nanoparticles obtained by the proposed method have a comparatively high specific magnetisation and a uniform size distribution. Therefore the developed materials can be used for the production of magnetorheological fluidsand creation of magnetically controlled capsules for targeted drug delivery and disease diagnostics in biology and medicine (magnetic resonance imaging).
References1. Gubin C. G., Koksharov Yu. A., Khomutov G. B.,Yurkov G. Yu. Magnetic nanoparticles: preparation,structure and properties. Russian Chemical Reviews2005;74(6): 539–574. Available at: https://www.elibrary.ru/item.asp?id=90858192. Skumr yev V. , Stoyanov S. , Zhang Y. ,Hadjipanayis G., Givord D., Nogués J. Beating thesuperparamagnetic limit with exchange bias. Nature.2003;423(6943): 850–853. DOI: https://doi.org/10.1038/nature016873. Joseph A., Mathew S. Ferrofluids: syntheticstrategies, stabilization, physicochemical features, characterization, and applications. ChemPlusChem.2014;79(10): 1382–1420. DOI: https://doi.org/10.1002/cplu.2014022024. Mathew D. S., Juang R.-S. An overview of thestructure and magnetism of spinel ferrite nanoparticlesand their synthesis in microemulsions. ChemicalEngineering Journal. 2007:129(1–3): 51–65. DOI:https://doi.org/10.1016/j.cej.2006.11.0015. Rewatkar K. G. Magnetic nanoparticles:synthesis and properties. Solid State Phenomena.2016:241: 177–201. DOI: https://doi.org/10.4028/www.scientific.net/ssp.241.1776. Tartaj P., Morales M. P., Veintemillas-VerdaguerS., Gonzalez-Carre´no T., Serna C. J. Thepreparation of magnetic nanoparticles for applicationsin biomedicine. Journal of Physics D: Applied Physics.2003: 36 (13): 182–197. DOI: : https://doi.org/10.1088/0022-3727/36/13/2027. West A. Khimiya tverdogo tela. Teoriya iprilozheniya [Solid State Chemistry and Its Applications].In 2 parts Part 1. Transl. from English. Moscow, Mir,1988 558 p.8. Spravochnik khimika: V 6 t. 2-e izd. Obshchiyesvedeniya. Stroyeniye veshchestva. Svoystva vazhneyshikhveshchestv. Laboratornaya tekhnika [Chemist’sHandbook: In 6 volumes, 2nd ed. General information.The structure of matter. Properties of the mostimportant substances. Laboratory equipment]. B. P.Nikolskiy (ed.) Moscow – Leningrad: GoskhimizdatPubl.; 1963. V. 1. 1071 p. (In Russ.)9. Zhuravlev G. I. Khimiya i tekhnologiya ferritov[Ferrite chemistry and technology]. Leningrad:Khimiya Publ.; 1970. p. 192. (In Russ.)10. Mason B. Mineralogical aspects of the systemFeO-Fe2O3-MnO-Mn2O3. Geologiska Föreningen iStockholm Förhandlingar. 1943;65(2): 97–180. DOI:https://doi.org/10.1080/1103589430944714211. Guillemet-Fritsch S., Navrotsky A., TailhadesPh., Coradin H., Wang M. Thermochemistry of ironmanganese oxide spinels. Journal of Solid StateChemistry. 2005;178(1):106–113. DOI: https://doi.org/10.1016/j.jssc.2004.10.03112. Ortega D. Structure and magnetism in magneticnanoparticles. In: Magnetic Nanoparticles: FromFabrication to Clinical Applications. Boca Raton: CRCPress; 2012. p. 3–72. DOI:https://doi.org/10.1201/b11760-313. Kodama T., Ookubo M., Miura S., Kitayama Y.Synthesis and characterization of ultrafine Mn(II)-bearing ferrite of type MnxFe3-xO4 by coprecipitation.Materials Research Bulletin... 1996:31(12): 1501–1512.DOI: https://doi.org/10.1016/s0025-5408(96)00146-814. Al-Rashdi K. S., Widatallah H., Al Ma’Mari F.,Cespedes O., Elzain M., Al-Rawas A., Gismelseed A.,Yousif A. Structural and mossbauer studies ofnanocrystalline Mn2+ doped Fe3O4 particles. HyperfineInteract. 2018:239(1): 1–11. DOI: https://doi.org/10.1007/s10751-017-1476-915. Modaresi N., Afzalzadeh R., Aslibeiki B.,Kameli P. Competition between the Impact of cationdistribution and crystallite size on properties ofMnxFe3–xO4 nanoparticles synthesized at roomtemperature. Ceramics International. 2017:43(17):15381–15391. DOI: https://doi.org/10.1016/j.ceramint.2017.08.079
