Study of structural magnetic and electrical properties of MFe2O4 spinel ferrites prepared by different synthesis routes for gas sensor applications

Abstract

newline A series of MnxZn1 xFe2O4 (x = 0.5, 0.6, 0.7) nanoferrites have been synthesized by sol-gel auto-combustion and co-precipitation methods in order to study their structural, microstructural, magnetic and di-electric properties including gas sensing properties. The samples are characterized by employing different experimental techniques such as X-ray diffraction (XRD), Scanning electron microscopy (SEM), Filed emission microscopy (FE-SEM), Energy dispersion X-ray spectrum (EDX),Fourier transform infrared spectroscopy (FT-IR), Electron spin resonance (ESR), Vibrating sample magnetometer (VSM), Zero field cooling (ZFC) and Filed cooling (FC) measurements, Mössbauer spectroscopy, Impedance analyzer (di-electric measurements) and finally gas sensor techniques. newlineThe XRD patterns of the ferrite samples prepared by the two methods revealed the cubic spinel structure belonging to fd3m space group. The ferrite samples prepared by sol-gel auto combustion method are prone to have secondary phases than the samples prepared by co-precipitation method. The secondary phases seem to affect their structural parameters. The grain sizes and crystallite sizes are showing the effect on structural and elastic properties. The dependence of Mn2+ substitution Zn-ferrite is studied in terms of their structural parameters. The vibrational bands observed for these compositions confirm the cubic spinel structure. The variation of force constants are in the line variation of tetrahedral and octahedral vibrational frequencies. FE-SEM revealed that the particles are in nanoscale dimensions and also distribution of particles in different sizes. newlineThe ESR spectra revealed the co-existence of Zn2+, Mn2+ and Fe3+ ions. The ESR parameters exhibit the variation of superexchange and di-polar interactions to understand the microscopic magnetic behaviour. The variation of lattice energy supports variation of molecular dynamics of present series of samples.