tructural and magnetic properties of La-doped strontium-hexaferrites ceramics obtained by spark-plasma sinterin

Autor(es)

Govea-Alcaide, E. ^{[1, 2]} ; Matilla-Arias, J. ^[2] ; Guerrero, F. ^[1] ; Marino-Castellanos, P. ^[3] ; Montero-Rey, K. ^[4] ; Rosales-Saiz, F. ^[2] ; Machado, I. F. ^[5]

Afiliação do(s) autor(es)

^[1] Univ Fed Amazonas, Dept Phys, Manaus, Amazonas - Brazil

^[2] Univ Granma, Fac Ciencias Tecn, Dept Ciencias Basicas & Informat Aplicada, Bayamo - Cuba

^[3] Univ Holguin, Fac Ciencias Nat & Agr, Dept Fis, Holguin - Cuba

^[4] Univ Sao Paulo, Inst Fis, Dept Fis Mat & Mecan, Sao Paulo, SP - Brazil

^[5] Univ Sao Paulo, Dept Engn Mecatron & Sistemas Mecan, Escola Politecn, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Magnetism and Magnetic Materials; v. 533, SEP 1 2021.
• Citações Web of Science: 0

Resumo

Polycrystalline samples of Sr1\_xLaxFe12O19 (x = 0.1, 0.3, and 0.6) hexaferrite were prepared by spark-plasma sintering (SPS) and its structural and magnetic properties have been investigated. The SPS process were performed under vacuum, at 900 C, and in only 5 min. X-ray powder diffraction patterns showed that before SPS sintering samples are composed by several phases where the SrFe12O19 (SrM) is not higher than 12%. From Rietveld refinement method, we have found that after SPS process the content of SrM phase increased, in mean, up to 68%. However, it was found the presence of secondary phase such as alpha-Fe2O3 and LaFeO3 (%) whose phase content also vary with increasing the La-content. A finite element simulation model were used to study the temperature evolution within the sample during the SPS treatment. Magnetization measurements at room temperature yielded values of saturation magnetization between - 43 to - 27 emu/g and coercivities, HcB, in the range 3.11 to 2.88 kOe with increasing x. The influence and possible interaction between detected magnetic phases was studied by means of first-order reversal curves (FORCs) measurements. Results indicated that magnetic behavior of the La-doped strontium hexaferrites obtained by SPS technique are analogous a system composed of a broad distribution particles that are exchange-coupled with a certain number of other of neighboring particles. From FORC maps the coercivity profiles of the studied samples were extracted. The asymmetric behavior of these profiles were related to a broad distribution of the particle size and/or the influence of the secondary magnetic phases. (AU)

• Processo FAPESP: 12/08068-0 - Síntese de amostras supercondutoras de (Bi,Pb)2Sr2Ca2Cu3O10+y (Bi-2223) pela técnica de spark plasma sintering
• Beneficiário: Renato de Figueiredo Jardim
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional