title: Shell-driven magnetic stability in core-shell nanoparticles.
abstract: The magnetic properties of ferromagnetic-antiferromagnetic Co-CoO core-shell nanoparticles are investigated as a function of the in-plane coverage density from 3.5% to 15%. The superparamagnetic blocking temperature, the coercivity, and the bias field radically increase with increasing coverage. This behavior cannot be attributed to the overall interactions between cores. Rather, it can be semiquantitatively understood by assuming that the shells of isolated core-shell nanoparticles have strongly degraded magnetic properties, which are rapidly recovered as nanoparticles come into contact.
authors.affiliation: Institució Catalana de Recerca i Estudis Avançats and Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Nogués
authors.forename: V
authors.initials: V
authors.lastname: Skumryev
authors.forename: J
authors.initials: J
authors.lastname: Sort
authors.forename: S
authors.initials: S
authors.lastname: Stoyanov
authors.forename: D
authors.initials: D
authors.lastname: Givord
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D013696:Temperature
chemical_list: D010087:Oxides; D003035:Cobalt; C060728:cobalt oxide