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@Article{PintoMachGomeReze:2019:InMoSt,
               author = "Pinto, Simone de Souza and Machado, Jo{\~a}o Paulo Barros and 
                         Gomes, Newton A. S. and Rezende, Mirabel Cerqueira",
          affiliation = "{Universidade Federal de S{\~a}o Paulo (UNIFESP)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Tecnol{\'o}gico de Aeron{\'a}utica (ITA)} and {Universidade 
                         Federal de S{\~a}o Paulo (UNIFESP)}",
                title = "The influence of morphology, structure, and weight fraction of 
                         magnetic additives on the electromagnetic characteristics of 
                         composites",
              journal = "Journal of Magnetism and Magnetic Materials",
                 year = "2019",
               volume = "484",
                pages = "126--138",
                month = "Ago",
             keywords = "Magnetic additives, Composites, Microwave absorber, Shielding 
                         effectiveness, Reflectivity.",
             abstract = "This study deals with different magnetic additives based on 
                         ferrites (MnZn, LaCa (Co and Ti)), carbonyl iron (CI), and iron 
                         filaments (IF) formulated in epoxy resin. Morphological and 
                         structural characteristics of the additives were evaluated. Based 
                         on these additives samples with both different thickness and 
                         weight fractions (170 wt%) were prepared. The formulated 
                         composites were analyzed considering different electromagnetic 
                         characteristics: reflectivity, shielding effectiveness, the 
                         complex parameters of dielectric permittivity (\ε) and 
                         magnetic permeability (), and the corresponding loss tangents in 
                         the microwave X-band. Scanning electron microscopy assisted with 
                         energy-dispersive spectrometry (SEM-EDS) analyses show that the 
                         additives have different morphologies, with varied sizes, shapes, 
                         and compositions. X-ray diffraction (XRD) analyses allowed 
                         determining the structural phases of the magnetic additives: CI 
                         and IF are constituted by Fe-\α phase, the ferrite of MnZn 
                         has an unique phase, and the two ferrites of LaCa-Co and LaCa-Ti 
                         have the same phase in the presence of different metallic oxides. 
                         In general, the complex parameters of \ε and  increased 
                         with the additive concentration increase in the composites, as 
                         expected, considering the magnetic characteristics of all 
                         additives studied. Reflectivity measurements show different 
                         attenuation values with promising results for composites based on 
                         CI, IF, and MnZn ferrite. The composites based on the ferrites 
                         show the worst performance on the reflectivity measurements. The 
                         shielding effectiveness measurements show good results (20 dB) 
                         over the entire X-band for specimens based on the LaCa-Co ferrite. 
                         In this case, the dominant shielding mechanism is due to the 
                         multiple scattering (SEM) in the material.",
                  doi = "10.1016/j.jmmm.2019.03.085",
                  url = "http://dx.doi.org/10.1016/j.jmmm.2019.03.085",
                 issn = "0304-8853",
             language = "en",
           targetfile = "souza_influence.pdf",
        urlaccessdate = "25 nov. 2020"
}


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