title: The magnetization processes and critical transition in a nanogranular magnetic film with perpendicular anisotropy.
abstract: The mechanisms and properties of the equilibrium magnetization process for nanogranular films with perpendicular anisotropy placed in a tilted magnetic field are considered. The contributions of the effects of canting and flipping of the granules' magnetic moments to the process of film magnetization are studied. A critical behavior of the film magnetization at the transition, induced by a tilted magnetic field, from a state with non-uniform orientation of the granules' magnetic moments to one with a similar orientation is revealed. The results obtained within the two-level model of the orientation of the particles' magnetic moments are in good agreement with the experimental data for Co-Al(2)O(3) (61 at.% Co) granular film. The perpendicular anisotropy of the granules in this film originates mainly from their elongated shape. It is shown that in the non-uniform state the magnetostatic energy of a granular film with similarly oriented elongated granules can be described by the sum of contributions of two types: quasi-single-granular and quasi-film. The effective constant of the single-particle anisotropy of the granules in this case turns out to be dependent on the factor of volume filling of the film by granules, but not on its magnetization.
authors: Institute of Physics of the NAS of Ukraine, Kyiv 03680, Ukraine. vmkalita@ukr.net
authors: V M
authors: VM
authors: Kalita
authors: A F
authors: AF
authors: Lozenko
authors: S M
authors: SM
authors: Ryabchenko
authors: A V
authors: AV
authors: Los
authors: A V
authors: AV
authors: Sitnikov
authors: O V
authors: OV
authors: Stognei
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D016880:Anisotropy; D003035:Cobalt / Q000737:chemistry*; D060328:Magnetic Phenomena; D053768:Metal Nanoparticles / Q000737:chemistry*; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*
chemical_list: D003035:Cobalt; D000537:Aluminum Oxide