Magnetic states of nanostructures containing Ni²⁺ ions at the surface of SiO₂ nanospheres.

ABSTRACT: Ultra-small magnetic particles containing Ni²⁺ ions were grown at the surface of SiO₂ spheroidal nanoparticles (typical diameter: 50 nm) starting from NiCl₂ solutions. Depending on preparation details, two samples characterized by magnetic sub-nanostructures or lamellar sub-nanoparticles at the SiO₂ nanosphere surface were obtained. The decorated SiO₂ nanospheres were submitted to physico-chemical and magnetic characterization. In both samples, a magnetically blocked phase is observed at low temperature. Below 5 K, discontinuities in isothermal magnetization loops and magnetic relaxation effects suggest the onset of coherent quantum tunneling of nanoparticle magnetization (QTM). Relaxation effects give are described by a field- and tem

SUBMITTER: Barrera G 

PROVIDER: S-EPMC5589877 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature