Exploring gas sensing, magnetic and dielectric properties of Ni2+ modified Mn–Zn ferrites.

In the present report, pristine and Ni2+ modified Manganese Zinc ferrites (Mn–Zn ferrites) [Mn 0·5 Zn 0.5 Ni x Fe 2-x O 4 , where x = 0.0, 0.025, 0.05] were synthesized using combustion method. Structural characterization revealed all the composition exhibit face-centered cubic crystallinity with space group F d 3 ‾ m without any secondary phases. FTIR spectra showed high frequency bend located at 652 cm−1 which confirmed the formation of Mn 0·5 Zn 0.5 Ni x Fe 2-x O 4 (x = 0.0, 0.025, 0.05) NPs as the high frequency kink attributes to Fe/Ni–O stretching vibration in cubic ferrite structure. Surface morphology and granular microstructure of all the compositions was determined using Scanning Electron Microscopy (SEM) and it was observed that compositions possessed porous micro-grains with average size of ∼20 μm. The average particle size increased from 5.5 ± 0.34 nm to 11.29 ± 0.12 nm with Ni2+ substitution in Mn–Zn ferrites. The optical energy band (Eg) slightly increased from 1.925 to 2.036 eV with increasing Ni2+ content as derived from UV–Visible spectral studies. The saturation magnetization enhanced with increasing Ni2+ concentration in the crystal framework of Mn–Zn ferrites. The real part of dielectric constant also increases with increasing Ni2+ concentration in the Mn–Zn ferrites. The gas sensing response of all the compositions was also analyzed for liquified petroleum gas (LPG). The sensitivity of all the compositions was also investigated on LPG, carbon monoxide (CO), and acetone gases and it was observed that the composition with higher concentration of Ni2+ depicted maximum response against all the gases, but in case of LPG the sensor showed maximum response. The sensing response was also checked at different operating temperature and time. The observed results support the potential candidature of Mn 0·5 Zn 0.5 Ni x Fe 2-x O 4 , where x = 0.0, 0.025, and 0.05 NPs as LPG gas sensor. [ABSTRACT FROM AUTHOR]