Structural, magnetic and microwave absorption performances of MnxZn(1-x)Fe2O4 nanopowders via high-temperature mechanochemical method

As a typical microwave absorption material (MAM), ferrite is frequently employed within the domain of electromagnetic wave absorption (EMWA). In this work, through adopting a novel and promising high-temperature mechanochemical (HTMC) method, pure-phase spinel Mn x Zn (1- x ) Fe 2 O 4 nanopowders (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) with a spherical structure were fabricated. The powders' chemical compositions and structures, microscopic morphology, and static magnetic characteristics (Ms, Mr, and Hc) were examined, along with their electromagnetic parameters and EMWA capabilities in 2-18 GHz. The outcomes demonstrate that the static magnetic characteristics and dynamic electromagnetic performances of the Mn x Zn (1- x ) Fe 2 O 4 nanopowders can be significantly affected by the manganese content. The static magnetic characteristics and EMWA performances of the as- prepared powders can all be enhanced with a promotion in manganese content, which may be related to the Zn2+ substitution. Among these, at a matching thickness of 4.4 mm, the MnFe2O4 powder obtains a minimum reflection loss of-54.7 dB (equivalent to 99.9997 % of the EMWA), at which point the effective absorption bandwidth approaches 3.9 GHz. The superior EMWA performance of as-prepared Mn x Zn (1- x ) Fe 2 O 4 nanopowders is attributable to the favorable cooperative impact between dielectric and magnetic losses, as well as the multiple reflection and scattering of electromagnetic waves between the Mn x Zn (1- x ) Fe 2 O 4 particles, which lengthens the dissemination path of electromagnetic waves and strengthens the loss effect. Therefore, the as-prepared MnxZn(1- x ) Fe 2 O 4 nanopowder can be utilized in the field of high-efficiency EMWA, and the HTMC method has considerable potential for the large-scale preparation of high-performance MAMs.