Pecularities of the magnetic structure and microwave properties in Ba(Fe1-xScx)12O19 (x<0.1) hexaferrites

The peculiarities of the fine atomic and magnetic structure, magnetic properties and microwave characteristics under Sc-substitution were investigated in Ba(Fe1-xScx)(12)O-19 (x <= 0.1) solid solutions. Structural data was obtained using neutron powder diffraction with high resolution on atomic level and was described in the frame of standard P6(3)/mmc Space Group. Almost linear increase of the main lattice parameters and internal stress was explained by the difference in ionic radius of Fe3+ and Sc3+. Magnetic properties were determined by VSM and discussed in terms of Mossbauer studies. The non-linear behavior of the magnetic parameters was explained by the features of Sc3+ ions distribution in the hexaferrite structure and some deviation from strict collinearity in the direction of the magnetic vector. Concentration dependence of coercivity in the concentration range x >= 0.05 was explained by rapid frustration of the magnetic structure (destruction of the magnetic long range ordering due to weakening of the intrasublattice exchange interaction in Fe3+-O2-Fe3+ in the first and second coordination spheres). Microwave properties were investigated using a co-axial method in the high frequency range (20-60 GHz). It has been demonstrated that the nature of electromagnetic absorption in Ba(Fe1-xScx)(12)O-19 (x <= 0.1) solid solutions is caused by natural ferromagnetic resonance. A good correlation was established between the theoretical calculation of the resonant frequency and the experimental results. It opens broad prospects for practical applications of substituted hexaferrites at higher frequencies. (C) 2019 Elsevier B.V. All rights reserved.