Fabrication of exchange coupled hard/soft magnetic nanocomposites: Correlation between composition, magnetic, optical and microwave properties

This paper studied the exchange coupling performance beside structural and microwave properties of SrFe12O19 (SFO) and x(CoTm0.01Tb0.01Fe1.98O4) (CoTmTb) (x <= 3.0) hard/soft ferrites nanocomposites (NCs). The structure and morphology of NCs were investigated by XRD, SEM, TEM and HR-TEM. Diffuse reflectance spectroscopic (DRS) measurements were applied on hexagonal ferrite, on spinel ferrite nanoparticles and on hard/soft NCs to specify the optical properties. Estimated E-g data are in a range between 1.32 and 1.79 eV. The magnetic properties were also inspected via measurements of magnetization (M) against magnetic field (H) at 300 K (RT) and 10 K (LT). The measurements performed at RT along with the plots of dM/dH versus H indicated that the NCs display good magnetic properties (exchange coupling behavior). The magnetic parameters such as (M-s, M-r, and H-c) show an enhancement in their values with an increasing the soft content at RT. Similarly, the maximum energy product (BH)(max) rises and reaches its max value for SFO/3(CoTmTb) NCs. Microwave properties of the SFO/x(CoTmTb) NCs were measured in the frequency range 33-50 GHz. From measured S11 and S21 parameters the main electrodynamic characteristics - permittivity and permeability (real and imaginary parts) were computed. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.

Automated summary

This paper investigated the structural, optical, and magnetic properties of SrFe12O19 and CoTmTb hard/soft ferrite nanocomposites, revealing an enhancement in magnetic parameters with an increase in soft content and the highest energy product value reached in SFO/3(CoTmTb) NCs. Microwave properties were also measured in the frequency range 33-50 GHz, showing main electrodynamic characteristics like permittivity and permeability.