Naslov
Structural characterization of NiCoB nanoparticles using FE-SEM, EDX and XRD

Autori
Lončarek, Ivana ; Tonejc, Anđelka ; Tonejc, Antun ; Novosel, Nikolina ; Babić, Emil ; Zadro, Krešo ; Mustapić, Mislav ; Bijelić, Mirjana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Nineteenth Slovenian-Croatian Crystallographic Meeting : book of abstracts / Lah, Nina ; Leban, Ivan - Ljubljana, 2010

Skup
Slovenian-Croatian Crystallographic Meeting (19 ; 2010)

Mjesto i datum
Strahinj, Slovenija, 16.06.2010. - 20.06.2010

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
X-ray powder diffraction; field emission scanning electron microscopy; energy dispersive X-ray analysis; superconducting quantum interference device magnetometer; nearly uniaxial nanoparticles; superparamagnetic behaviour

Sažetak
In the last years considerable attention has been devoted to materials composed of fine magnetic particles because of their novel properties (superparamagnetism) and technological applications. Magnetic nanomaterials are also very intriguing due to their potential application in biomedicine [1-3]. A well known method for preparation of alloys in the form of fine particles (particularly ternary transition metal-boron alloys e.g. NiCoB) is the chemical reduction of aqueous solution of metal salts, with an alkali metal borohydride as the reducing agent. By changing the composition and synthesis conditions it is possible to control the morphology (i. e. size and shape) of these nanoparticles. It is known that magnetic particles smaller than 100 nm could exhibit superparamagnetism [4], and we suppose that such particles embedded in MgB2 superconductor (Tc39 K) could enhance the critical current density. At this stage of research we have tried to synthesize amorphous nanosized particles with well defined dimensions and with narrow and reproducible size distribution in order to obtain superparamagnetic behaviour. Two series of samples were prepared and analyzed, namely NiCoB without and with SiO2 coating. We suppose that particles with SiO2 coating could be more appropriate for embedding in MgB2 superconductor because the SiO2 coating could prevent a direct contact among NiCoB particles and decrease the magnetic interaction among the particles. The resulting microstructures were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX). For magnetic measurements superconducting quantum interference device (SQUID) magnetometer was used. The analysis of FE-SEM micrographs of NiCoB/NiCoB-SiO2 nanoparticles showed that the particles were nearly uniaxial ( ili: particle shapes were roughly spheres ), with sizes from 12 to 24 nm for NiCoB sample and from 12 to 32 nm for the SiO2 coated NiCoB sample, showing relatively narrow log normal distribution. X-ray diffraction patterns showed that the samples were amorphous. EDX results confirmed the existence of expected elements (Ni, Co, B, Si and O). Also, the preliminary magnetic measurements for both samples confirmed the superparamagnetic behaviour. [1] A. K. Gupta, S. Wells, IEE Trans. Nanobiosci. 3 (2004) 66-73 [2] A. H. Lu, E. L. Salabas, F. Shuf, Angew. Chem. Int. Edn 46 (2007) 1222-44 [3] J. F. Lutz, S. Stiller, A. Hoth, L. Kaufner, U. Pison, R. Cartier, Biomacromolecules 7 (2006) 3132-8 [4] A. G. Roca, R. Costo, A. F. Rebolledo, S. Veintemillas-Verdaguer, P. Tartaj, T. González-Carreño, M. P. Morales , C. J. Serna, J. Phys. D:Appl. Phys. 42 (2009)

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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