Yttrium iron garnet heterocoagulated by silica

• Autor(a) principal: Godoi, Ricardo H.M.
• Data de Publicação: 2002
• Outros Autores: Marques, Rodrigo Fernando Costa [UNESP], Varanda, Laudemir C. [UNESP], Jafelicci Júnior, Miguel [UNESP]
• Tipo de documento: Artigo de conferência
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1109/TMAG.2002.801964; http://hdl.handle.net/11449/66964
• topic: Heterocoagulation; Silica on YIG ferrite; Surface anisotropy; Yttrium iron garnet; Anisotropy; Garnets; Hydrolysis; Interfaces (materials); Magnetic fluids; Precipitation (chemical); Transmission electron microscopy; Yttrium compounds; Silica

Coated purpose of homogeneous distribution as a second phase is introduced in magnetic systems. Yttrium iron garnet (YIG) shows special interest as magnetic dye, microwave absorber, and magnetic fluids when heterocoagulated by other material. Surface and interface magnetic properties are intimately connected with the new properties of the silica on YIG system. Néel first introduced the concept of surface anisotropy, and Chen et al. developed a model that describes the anisotropy effects at the boundary surface particle, which was applied in this work. Spherical YIG particles were prepared by coprecipitation method and coated with silica using the tetraethylorthosilicate (TEOS) hydrolysis process. The silica-YIG boundary was investigated by transmission electron microscopy. Hysteresis loops comparatively show the profile of the naked and silica-covered YIG particles. The surface anisotropies were calculated using the Chen et al. approach. Indeed, in heterocoagulation systems, the surface anisotropy is a result of the interface symmetry breaking, as observed.