Magnetic and electromagnetic properties of RuZn and RuCo substituted BaFe 12O 19

• Published in: Journal of magnetism and magnetic materials Vol. 260; no. 3; pp. 437 - 446
• Main Authors: Pignard, S, Vincent, H, Flavin, E, Boust, F
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2003
• Subjects: Ferrimagnetism; Hexaferrite; Magnetic anisotropy; Microwave absorption; Powder diffraction; 61.10.Nz; 76.50.+g; Microwave absorption; Ferrimagnetism; 81.20.Ev; Magnetic anisotropy; Hexaferrite; Powder diffraction; 75.30.Gw
• ISSN: 0304-8853
• DOI: 10.1016/S0304-8853(02)01387-2

Polycrystalline samples of M-type hexaferrites BaFe 12−2 x Ru x Zn x O 19 and BaFe 12−2 x Ru x Co x O 19 with 0⩽ x⩽0.45 have been prepared by a classical sintering method. The evolutions with x of the cell parameters, the saturation magnetization and the magnetic transition temperature have been measured; in this range of small doping ratios, saturation magnetization and Curie temperature of substituted hexaferrites remain close to those of the undoped BaFe 12O 19. X-ray diffraction measurements on oriented powders show that a change of magnetocrystalline anisotropy from axial to planar occurs in both cases for a small substituting ratio x c=0.375. Microwave electromagnetic characteristics have been studied on the ceramic samples from 0.1 to 10 GHz. The behaviour of the magnetic losses ( μ″) corroborates the anisotropy change when doping; a convolution of the dissipation mechanisms (domain wall motions and gyromagnetism) is obtained for x c. The level of the magnetic losses is discussed in relation with others substituted Ba-hexaferrites.