Microstrutural Features of Magnetic NiCoB Nanoparticles Addition to MgB2 Precursor Powders

Lončarek, Ivana and Tonejc, Anđelka and Skoko, Željko and Novosel, Nikolina and Mustapić, Mislav (2017) Microstrutural Features of Magnetic NiCoB Nanoparticles Addition to MgB2 Precursor Powders. Croatica Chemica Acta, 90 (1). pp. 37-51. ISSN 0011-1643

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Abstract

Magnesium diboride (MgB2) is a superconductor characterized by interesting properties like rather high superconducting transition temperature Tc = 39 K, long coherence length and low anisotropy. In addition, it has a very simple crystal structure and low density. Those properties make the MgB2 an ideal candidate for a wide range of applications. To improve the electromagnetic properties of MgB2, magnetic nickel-cobalt-boron (NiCoB) nanoparticles (mean grain size 17 ± 3 nm) were added to Mg and B precursor powders and sintered at 650 °C, i.e. the temperature of MgB2 superconductor formation. The nearly spherical NiCoB nanoparticles, as-prepared by the chemical reduction of metallic salts, were amorphous according to previous study. The resulting MgB2 sample, formed after the sintering at 650 °C, was subjected to detailed microstructural analysis which included the application of various experimental methods: XRD, FE-SEM, EDS, elemental mapping, TEM and SAED. The methods confirmed the formation of new crystal CoNi phase (due to heat treatment at 650C), consisting of spherical nanoparticles (~ 6 nm) with tendency to spherical agglomerates formation. Those nanosized magnetic particles (characterized by the single domain magnetic structure and blocking temperature TB below room temperature), located at MgB2 grain boundaries, could serve as effective magnetic pinning centers in MgB2, thus improving its electromagnetic properties

Item Type: Article
Keywords: magnesium diboride, CoNi nanoparticles, X-ray diffraction, Rietveld refinement, scanning electron microscopy (SEM), transmission electron microscopy (TEM)
Date: 8 June 2017
Subjects: NATURAL SCIENCES > Physics
Additional Information: This work is licensed under a Creative Commons Attribution 4.0 International License. Received: August 31, 2016. Revised: March 7, 2017. Accepted: March 13, 2017.
Divisions: Faculty of Science > Department of Physics
Project code: 119-0982886-1009
Publisher: Hrvatsko kemijsko društvo
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 23 Oct 2017 06:52
Last Modified: 23 Oct 2017 06:52
URI: http://digre.pmf.unizg.hr/id/eprint/5614

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