Some peculiarities in the magnetic behavior of aerosol generated NiO nanoparticles

• Published in: Journal of alloys and compounds Vol. 572; pp. 150 - 157
• Main Authors: Morozov, Yu.G., Ortega, D., Belousova, O.V., Parkin, I.P., Kuznetsov, M.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.09.2013
• Subjects: Aerosols; Alloys; Diamagnetic susceptibility; Diffraction; Ferromagnetism; Levitation-jet method; Magnetic fields; Magnetization; Magnetization curves; Nanoparticles; Nickel oxide (NiO); Specific surface; Transmission electron microscopy; Nanoparticles; Specific surface; Levitation-jet method; Magnetization; Nickel oxide (NiO); Diamagnetic susceptibility
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.03.260

[Display omitted] •Structural and magnetic characterization of cubic-shaped aerosol NiO nanoparticles.•Procedure for subtracting an underlying diamagnetic contribution.•Correlation between specific surface area of NPs and their diamagnetic susceptibility.•Critical transition temperature associated to a hypothetical superconductive state. Nickel oxide nanoparticles (NPs) 6–24nm size have been prepared by a levitation-jet method based on metal vapor condensation in a mixture of gaseous streams of helium and air (or oxygen). Particles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) N2 adsorption and SQUID magnetometry. It is revealed that at room-temperature (RT) the nanoparticles show a small magnetic moment and the magnetic field dependence of their susceptibility a minimum lying below the high-field values. After the appropriate subtraction of both ferromagnetic and paramagnetic components from the initial magnetization curves, the appearance of a diamagnetic contribution is observed. The possible link between the latter contribution and the occurrence of some features related to RT superconductivity in NiO NPs is discussed.