Influence of samarium on the structural, magnetic, and gas sensing performance of cadmium zinc ferrites

Abstract

Cadmium zinc ferrites Cd0.5Zn0.5SmxFe2−xO4 nanoparticles were synthesized with different concentrations x = 0.00, 0.01, 0.02, 0.04, 0.06, and 0.08, via the wet chemical co-precipitation method. The effects of the Sm3+ doping on the structural, morphological, compositional, and magnetic properties have been investigated. The structural analysis is performed using x-ray diffraction (XRD) with Rietveld refinement. The results indicate great crystallinity in the FCC Fd3m spinel structure of Cd0.5Zn0.5SmxFe2−xO4 nanoparticles. The crystallite size was estimated using Debye–Scherrer, Williamson–Hall, Size-strain plot (SSP), and Halder-Wagner (H-W) methods. It revealed a decreasing trend with the increase of Sm-doping concentrations until the solubility limit at around x = 0.04. The spherical morphology of the samples was investigated using transmission electron microscopy (TEM) with minor agglomeration as a benefit of using the capping agent polyvinylpyrrolidone (PVP). Raman spectroscopy validates the incorporation of trivalent Sm3+ in the octahedral sites. X-ray photoelectron spectroscopy (XPS) verified the elemental compositions as well as the purity of the samples and the incorporation of the dopants. A vibrating sample magnetometer (VSM) was used to study the magnetic properties, and which indicates the superparamagnetic behavior of the prepared samples. The prepared samples were tested as liquefied petroleum gas (LPG) sensors by studying their sensitivity, optimum working temperature, response time, and recovery time. The doping of samarium ions reveals a great increase in LPG sensing sensitivity and optimum temperature with decreasing response and recovery times.