spectroscopy, SQUID VSM were carried out to investigate phase formation, microstructural and influence
of Cu doping on magnetic properties of NiFe2O4 thin films. The gas response towards various gases viz.
ethanol, Liquid Petroleum Gas (LPG), methanol and hydrogen sulfide (H2S) is investigated. The results of
XRD revealed that all samples had shown the principal phase of nickel ferrite and the lattice parameter
was found to vary from 8.294 Å to 8.314 Å on an incorporation of Cu, and the crystalline sizes were about
40e45 nm. The effect of Cu concentration on saturation magnetization and coercive force were studied.
The maximum value of saturation magnetization calculated from hysteresis loop was 89.16 emu/g at
room temperature and 96.88 emu/g at 50 K. Cu content on the film surface was found to be maximum for
1 wt% Cu:NiFe2O4 thin film and this film showed an improved response towards all gases. Response of
ethanol for NiFe2O4 thin film was found to be higher as compared to all the other gases. The lowering of
the optimum operating temperature is observed in 1 wt% Cu:NiFe2O4 thin film with higher selectivity
towards ethanol than other gases. All results indicated that the Cu doping in nickel ferrite thin films has a
significant influence on the properties.