Nanoscale Physics

Magnetic properties of Fe3O4:Gd:B nanostructured complex, promising for applications in oncotherapy
Shanina B.D.1, Krasnovyd S.V.1, Konchits A.A.1, Petranovs’ka A.L.2, Shevchenko Yu.B.3
1 Department of Optics and Spectroscopy, Institute of Semiconductor Physics of the NAS of Ukraine. Prospect Nauki, 41, Kyiv-03028, Ukraine. 
E-mail: sergkrasnovyd88@gmail.com
2 Department of  nanomaterials, Chuiko Institute of Surface Chemistry of the NAS of Ukraine. General Naumov str. 17, Kyiv, 03164, Ukraine.
3 Center for Environmental Problems of Atomic Energy, Institute for Nuclear Research of the NAS of Ukraine. Prospect Nauky, 47, Kyiv 03028, Ukraine. 

Nanoparticles (NPs) are widely used today in many fields, including biology and medicine. Among them, the Fe3O4:Gd:B nanostructured complex is promising for neutron capture oncotherapy. In this work, the magnetic resonance properties of the Fe3O4:Gd:B complex in aqueous solution are studied for a number of samples of various compositions, namely: 1- Fe3O4; 2- Fe3O4:B=1:10; 3- Fe3O4:Gd=1:1; 4- Fe3O4:Gd:B=1:1:10; 5- Fe3O4:Gd=1:10; 6- Gd only. 
It was found that samples 1, 2, and 3 with a predominance of Fe3O4 NPs exhibit superparamagnetic behavior. In this case, the resonant field Hres is determined by the magnetization of the Fe3O4 particles: Hres = Hres, 0  4M. Here Hres,0 is the resonance field for one paramagnetic spin; M=MsV is the magnetic moment of the ferromagnetic nanoparticle with size L, V is a particle volume proportional to L3; Ms is a saturation magnetization Ms=446 emu·cm-3. Samples 5 and 6 exhibit paramagnetic behavior. Sample 4 demonstrates an intermediate type, in which the paramagnetic behavior is modified by the influence of superparamagnetic NPs of magnetite. 
Thus, within the framework of the above approach, both the general magnetic resonance properties of the Fe3O4:Gd:B complex and the separated contributions of individual components, including the contribution of gadolinium, were determined. 

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