Low Temperature and Surfactant-Free Hydrothermal Synthesis of CoNi Nanoparticles: Structure, Microstructure, and Magnetic Properties

Journal Article · Sun Sep 15 00:00:00 EDT 2019 · Journal of Superconductivity and Novel Magnetism

DOI:https://doi.org/10.1007/S10948-019-5056-X· OSTI ID:22922881

Bensouilah, A. ^[1]; Hemmous, M. ^[2]; Martínez-Blanco, D. ^[3]; Gorria, P. ^[4]; Blanco, J. A. ^[5]

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1. USTHB, LPM, Faculty of Physics (Algeria)
2. Nuclear Research Centre of Algiers (Algeria)
3. University of Oviedo, SCTs, EPM (Spain)
4. University of Oviedo, Department of Physics & IUTA, EPI (Spain)
5. University of Oviedo, Department of Physics (Spain)

We report on the synthesis of Co{sub 30}Ni{sub 70} nanoparticles using hydrothermal method at low temperatures and short times (100 °C, 2 h) without any surfactant or external magnetic field. The effect of NaOH concentration on the crystal structure, microstructure, and magnetic properties of CoNi samples has been investigated by x-ray diffraction (XRD), scanning (SEM) and high-resolution transmission (HRTEM) electron microscopy, and vibrating sample magnetometry (VSM). From the Rietveld refinement of x-ray powder diffraction patterns, we have evidenced the coexistence of two phases with face-centered cubic (FCC) and hexagonal (HCP) crystal structures, being 12 nm and 3 nm, respectively, the values for the mean grain size of both phases. SEM images show that the basic microstructure is composed of quasi-spheres and a chain-like morphology appears with increasing the amount of NaOH. HRTEM images evidence the formation of such chains, and confirm the coexistence of FCC and HCP phases. The magnetic hysteresis loops show a clear dependence of the coercivity on the particle morphology indicating the role played by the magnetic shape anisotropy.

• OSTI ID: 22922881
• Journal Information: Journal of Superconductivity and Novel Magnetism, Vol. 32, Issue 9; Conference: ICSM2018: 6. International Conference on Superconductivity and Magnetism, Antalya (Turkey), 29 Apr - 4 May 2018; Other Information: Copyright (c) 2019 Springer Science+Business Media, LLC, part of Springer Nature; Country of input: International Atomic Energy Agency (IAEA); ISSN 1557-1939
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ANISOTROPY
COBALT COMPOUNDS
COERCIVE FORCE
FCC LATTICES
HCP LATTICES
HYDROTHERMAL SYNTHESIS
INTERMETALLIC COMPOUNDS
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MAGNETISM
NANOPARTICLES
NICKEL COMPOUNDS
SCANNING ELECTRON MICROSCOPY
SURFACTANTS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION