首页|Structural, dielectric and gas sensing properties of gadolinium (Gd3+) substituted zinc-manganese nanoferrites
Structural, dielectric and gas sensing properties of gadolinium (Gd3+) substituted zinc-manganese nanoferrites
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NSTL
Elsevier
Gadolinium (Gd3+) substituted zinc manganese ferrite nanoparticles with nominal compositions Zn0.7Mn0.3GdxFe2-xO4 (where x = 0.000; 0.025; 0.050; 0.075; 0.100) were successfully synthetized using co precipitation method. The synthetized powders were calcined at 500 & nbsp;C and furthermore pressed into pellets and thermally treated at 650 & nbsp;C for a second time to obtain a more compact material. For the 500 C thermal treated samples, X-ray analysis revealed the formation of pure spinel ferrite phase, meanwhile for the 650 C thermal treated samples secondary phases appear which indicate that some of Gd3+ ions aren't able to remain in the structure of ferrite. The morphology of samples was investigated using scanning electron microscopy (SEM) and the images show agglomerated spherical nanoparticles within 20-30 nm size range. The magnetization curves recorded in +/- 10 kOe range indicate a superparamagnetic behavior of the synthetized ferrite samples. At low frequencies, the Gd3+ substituted ferrite samples corresponding to x = 0.050, 0.075 and 0.100 exhibit a resonant behavior of the dielectric losses dependence, while at high frequencies the lowest value was found for the sample with x = 0.025. The introduction of Gd3+ ions in the ferrite structure leads to a non-monotonous variation of AC electrical conductivity, which decrease from 2.55 x10(-6) S/m to 3 x10(-7) S/m. The ferrite samples have shown a good and reproducible response to the saturated acetone vapors and the highest sensitivity value (53%) was obtained for Zn0.7Mn0.3Gd0.025Fe1.9O4 ferrite sample. The response and recovery time varies between 36 and 56 s, respectively 80-116 s and both of these are independent of Gd3+ content.
NSTL
Elsevier
