Structural, Raman, magnetic and dielectric properties of strontium doped nickel zinc low dimensional ferrites

In the present investigation, Strontium-doped Ni_0.5Zn_0.5-XSr_XFe₂O₄ (X = 0, 0.1, and 0.2) (NZSFO) nanoparticles were synthesized via auto-combustion technique using citric acid as a fuel. The study investigates the structural, optical, magnetic, dielectric, thermal, and electrochemical properties of NZSFO nanoparticles. Structural properties are examined through XRD and Rietveld refinement process, which confirms that the NZSFO nanoparticles are pure-phase cubic spinel structure with an Fd-3m space group. The crystallite sizes are decreased from 17 nm to 12 nm as determined by the Debye-Scherrer formula, which were corroborated by HR-TEM observations. FESEM-EDAX confirmed elemental mapping and shows that the nanoparticles are roughly spherical in nature. Optical bandgap values progressively reduced as strontium content increased in the NZSFO series. VSM study at room temperature revealed magnetic properties exhibiting ferrimagnetic behaviour with an increase in magnetic saturation in the range of +1T to -1T. Raman spectroscopy revealed five active modes, including A1g, Eg, and three F2g, confirming the structural purity of the synthesized materials. Dielectric and impedance studies indicated a frequency-dependent Wagner-type polarization. The photoluminescence emission profiles displayed notable variations in intensity and peak positions. Thermal stability analysis via TGA-DSC exhibited a total weight loss of 7.47 %, leaving a residual yield of 92.53 %. The electrochemical study revealed impressive specific capacitance values of 1166.6 Fg^-1, which significantly showed better results than other reported Nickel ferrites. These characteristics of NZSFO nanoparticles show it is a good candidate for magnetic device applications.