Nanocomposites and nanomaterials

The influence of La3+ doping on the structure and properties of Ni0,5Co0,5Fe2O4 synthesized by various methods
Starko I.Y., Tatarchuk T.R.
Department of Chemisrty, Vasyl Stefanyk Precarpathian National University, 57, Shevchenko Str.,Ivano-Frankivsk, 76018, Ukraine. 
E-mail: tatarchuk.tetyana@gmail.com

Spinel ferrite is one of the most common areas of research. They have attracted attention due to their possible application as adsorbents, photocatalysts, in magnetic hyperthermia etc. The well-known methods for ferrites synthesis are sol-gel auto-combustion method, co-precipitation method, hydrothermal method, microwave synthesis, etc. The structure and properties of ferrites could be altered by doping with rare-earth ions such as La, Sm, Gd, Dy, Yb, Er, Tb, Ce and Y.
The object of this study is Ni-Co ferrites doped with lanthanum ions. The Ni0,5Co0,5LaxFe2-xO4 (x=0.0, 0.025; 0.05, 0.075) nanoparticles were obtained by both techniques – sol-gel autocombustion  method (PVA as reducing agent and fuel) and co-precipitation method (NaBH4 as precipitator). Nickel nitrate (Ni(NO3)2·6H2O), cobalt acetate (Co(CH3COO)2·4H2O), ferric nitrate (Fe(NO3)3·9H2O) and lanthanum nitrate (La(NO3)3·9H2O) were used as precursors. 
The structural, morphological and magnetic properties of obtained nanoparticles were characterized by XRD, SEM, EDS, FTIR, and Mossbauer spectroscopy. The results of XRD indicate the formation of a single-phase cubic spinel with a space group Fd-3m. The second phase of the lanthanum oxide or lanthanum orthoferrite were not identified in the all samples. From the data of the XRD analysis, the lattice parameter and the crystallite size were calculated. The average crystallite size of the ferrites are in the range from 12 to 19 nm. The lattice parameter decreases with increasing of lanthanum ions content. The SEM results indicate that the particles are homogenous and slightly agglomerated. The EDS analysis indicates the formation of La-doped nickel-cobalt ferrites. The attempt has been made to in-depth study of their structural, morphological and functional properties.