Temperature dependence of the ferromagnetic resonance (FMR) for Mn x Co 1− x Fe 2 O 4 (0 ≤ x ≤ 1) nanoparticles

Ferromagnetic resonance was used to study the temperature dependence of mixed manganese-cobalt ferrite nanoparticles with a size range between 5 and 42 nm synthesized by the hydrothermal method. Structural characterization was carried out using X-ray diffraction, scanning, and transmission electron microscopy. M (H) curves as a function of the Mn 2+ content at 2.5 and 300 K, and FMR in the temperature range of 80 < T < 700 K were used for the magnetic characterization. Temperature dependence of the resonance field shows three regions that can be interpreted in terms of agglomeration, dispersion and superparamagnetism in the samples. The H R and Δ H_PP as a function of the temperature and Mn 2 + content allows us to elucidate the key characteristics of the deviation from the ideal superparamagnetic behavior observed by magnetic measurements and open up new research possibilities for evaluating interparticle interactions in nanoparticles. Graphic abstract