Peculiarities of the microwave properties of hard-soft functional composites SrTb0.01Tm0.01Fe11.98O19-AFe2O4 (A = Co, Ni, Zn, Cu, or Mn).

A V Trukhanov,M G Vakhitov,T I Zubar,M A Almessiere,D S Klygach,A Baykal,D I Tishkevich,M V Silibin,Y Slimani,S V Trukhanov,N A Algarou,D A Vinnik

doi:10.1039/d0ra05087c

Abstract

Herein, we investigated the correlation between the chemical composition, microstructure, and microwave properties of composites based on lightly Tb/Tm-doped Sr-hexaferrites (SrTb0.01Tm0.01Fe11.98O19) and spinel ferrites (AFe2O4, A = Co, Ni, Zn, Cu, or Mn), which were fabricated by a one-pot citrate sol–gel method. Powder XRD patterns of products confirmed the presence of pure hexaferrite and spinel phases. Microstructural analysis was performed based on SEM images. The average grain size for each phase in the prepared composites was calculated. Comprehensive investigations of dielectric properties (real (ε′) and imaginary parts (ε′′) of permittivity, dielectric loss tangent (tan(δ)), and AC conductivity) were performed in the 1–3 × 106 Hz frequency range at 20–120 °C. Frequency dependency of microwave properties were investigated using the coaxial method in frequency range of 2–18 GHz. The non-linear behavior of the main microwave properties with a change in composition may be due to the influence of the soft magnetic phase. It was found that Mn- and Ni-spinel ferrites achieved the strongest electromagnetic absorption. This may be due to differences in the structures of the electron shell and the radii of the A-site ions in the spinel phase. It was discovered that the ionic polarization transformed into the dipole polarization.

Highlights

Interdependent transition metal oxides demonstrate a broad range of uncommon phenomena, which can be used for practical applications.[1,2,3]
Many researchers have concentrated on complex metal oxides that are based on Fe ions
The most interesting materials for researchers are barium M-type hexaferrite (AFe12O19, where A 1⁄4 Ba, Sr, Pb) and solid solutions based on these complex metal oxides

Summary

Introduction

Interdependent transition metal oxides demonstrate a broad range of uncommon phenomena, which can be used for practical applications.[1,2,3] Electrical and magnetic characteristics are result of the collaborative effects of charge and spin ordering. To investigate the dielectric properties of the obtained STTFO/ AF2O4 composite samples, the real part 30 and imaginary part 300 of the complex permittivity 3 1⁄4 30 + i300 and conductivity C at the alternating current in the 1–8 Â 105 Hz frequency and 20–120 C temperature ranges were measured.

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Results

Conclusion