Superparamagnetic nickel particles in yttria-stabilized zirconia prepared by reduction of Pechini-derived solution

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2014-06, Vol.16 (6), p.1-7, Article 2426
• Main Authors: White, Joshua T., Reimanis, Ivar E., O’Brien, James R.
• Format: Article
• Language: English
• Subjects: Anisotropy; Carbon; Characterization and Evaluation of Materials; Chemical synthesis methods; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Density; Exact sciences and technology; Heat treatment; Inorganic Chemistry; Lasers; Magnetic properties and materials; Magnetic properties of nanostructures; Materials Science; Methods of nanofabrication; Nanocrystalline materials; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanotechnology; Nickel; Optical Devices; Optics; Photonics; Physical Chemistry; Physics; Reduction; Research Paper; Yttria stabilized zirconia; Zirconium dioxide
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-014-2426-y

The magnetic behavior of very fine metallic Ni (Ni 0 ) particles dispersed in a matrix of 10 % by mol (m/o) Y 2 O 3 -stabilized ZrO 2 (10YSZ) was examined. Specimens that nominally contained 0.1, 0.5, and 1 m/o Ni were prepared by a high-purity chemical synthesis method followed by a reduction treatment in H 2 . A 0.5 m/o Ni specimen was also made by heating in vacuum, within a carbon environment. dc and ac susceptibility measurements revealed the presence of superparamagnetic Ni 0 as well as Ni 2+ . A Stoner–Wohlfarth formulation was applied to determine that the average Ni 0 particle size was between 4 and 7 nm, and this was confirmed by transmission electron microscopy. The activation energy for single-domain particle spin reversal and K eff , the effective anisotropy constant, were determined. K eff was higher for the vacuum heat treatment specimen because it contained less residual organic material, and therefore a higher density of Ni 0 particles. It is shown that it is possible to make very fine Ni 0 particles in YSZ via a direct conversion from Ni nitrates.