Ferromagnetic resonance in granular thin films

• Tipo: Artigo em Revista Científica Internacional
• Data: 1999

Autores

G.N. Kakazei (Autor) Outra; Kravets, AF (Autor) Outra; Lesnik, NA (Autor) Outra; de Azevedo, MMP (Autor) Outra; pogorelov, y. g. (Autor) FCUP; sousa, j. b. (Autor) FCUP

Revista

Título: Journal of Applied Physics

Vol. 85

Páginas: 5654-5656

ISSN: 0021-8979

Editora: American Institute of Physics

Indexação

ISI Web of Knowledge - 69 Citações

Scopus - 76 Citações

Outras Informações

ID Authenticus: P-001-4KX

DOI: 10.1063/1.369830

Abstract (EN): A theoretical analysis has been done of the effects of granule size, shape, orientation, and concentration and the temperature effects on the ferromagnetic resonance (FMR) field H-r in granular thin films. The granular CoxAg1-x thin films with 0.2<x<0.85 (the volumetric filling factor 0.17<f<0.83) were prepared by electron-beam oblique coevaporation. Our room temperature FMR data show an abrupt change in the H-r(f) dependence at f = f(p) approximate to 0.3, the percolation point for this system (as evidenced from the magnetization and magnetoresistance measurements). This change is associated to the development of great clusters [ferromagnetic (FM) phase] beside single granules [superparamagnetic (SPM) phase] at f>f(p). For the Co-Ag system, persistence of a considerable SPM fraction is revealed by the superconducting quantum interference device data up to the highest f, and the effect at f = f(p) consists in a discontinuous jump of the H-r(f) slope. Otherwise, the FMR data for granular Fe-SiO2 films(15) reveal a discontinuous jump in H-r itself at f approximate to 0.28. The latter can indicate a 1st kind-like magnetic percolation transition in that material. Thus FMR studies can effectively probe the internal structural processes in granular magnetic systems. (C) 1999 American Institute of Physics. [S0021-8979(99)65608-0].

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 3