Preparations and characterizations of Ca doped Ni-Mg-Mn nanocrystalline ferrites for switching field high-frequency applications

Ca-doped Ni-Mg-Mn spinel ferrites with compositions of Ni0.5Mg0.3Mn0.2CaxFe2-xO4 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared via sol-gel auto-ignition technique. TGA/DTA, FTIR, XRD, FESEM, and VSM were employed to evaluate the thermal, spectral, structural, morphological, and magnetic features of Ca-doped Ni-Mg-Mn spinel ferrites. TGA/DTA curves show the weight loss in the sample. This weight loss was attributed to the oxidation and decomposition of the sample contents at a temperature of 500 degrees C. XRD reveals a single-phase structure of the Ni-Mg-Mn nano ferrites. A single-phase orthorhombic structure was confirmed for Ca-doped Ni-Mg-Mn ferrites. Structural parameters such as lattice parameter, 'da', 'db', 'dc', and 'dv' were evaluated using unit cell software. The absorption peaks at 427 to 538 cm(-1) confirmed the spinel structure, which was evaluated using FTIR. FESEM analyses showed that the agglomerations increased with the doping of Ca in Ni-Mg-Mn ferrites. Remanence, Y-K angles, saturation, coercive force, magnetic squareness, magnetic moment, and anisotropy constant were determined for Ca-doped Ni-Mg-Mn spinel ferrite samples. It is noticed that saturation increases from 29.157 to 51.322 emu/g, whereas remanence increased from 5.34 to 9.40 emu/g, respectively. The permeability, anisotropy constant, and magnetic moments were also found to increase with Ca doping. However, the Y-K angles increased with Ca concentration in Ni-Mg-Mn nano ferrites. In addition, the switching field distribution (SFD) and high-frequency response of all the Ca-doped Ni-Mg-Mn samples were also evaluated. Ca-doped Ni-Mg-Mn samples are suggested to be suitable for switching, filters, inductors, and microwave absorption applications because of the superparamagnetic nature of the prepared spinel ferrites.

Automated summary

Ca-doped Ni-Mg-Mn spinel ferrites exhibit excellent thermal, spectral, structural, and magnetic properties, making them suitable for applications in switching, filters, inductors, and microwave absorption.