SANTOS, P. T. A.; http://lattes.cnpq.br/2240395277573754; SANTOS, Polyana Tarciana Araújo dos.
Abstract:
The magnetic ferrites are ceramic materials, characterized by containing Fe203 as main
component and exhibit spontaneous magnetization in the absence of applied magnetic
field. The ferrites have achieved great industrial importance which may be used in a
wide range of applications ranging from the huge demand for the manufacturing of
electrical and electronic devices like magnetic soft and hard, until, as shippers
applications of drugs, electromagnetic radiation absorber between others. This study
aims to investigate the effect of doping of 0,3 mol of Al3+ and 0,1 mol of Cu2+ on the
structure, morphology and magnetic characteristics of Ni-Zn ferrite synthesized by
combustion reaction using a stainless steel container and as a source of resistance
heating spiral. The samples were characterized by X-ray diffraction (XRD), chemical
analysis by X-ray fluorescence, energy dispersive (EDX), infrared spectroscopy (FITR),
scanning electron microscopy (SEM), N2 adsorption, and measures magnetic. The
results showed the formation of inverse spinel phase of Ni-Zn ferrite for samples as
synthesized, after calcination. For the composition doped with 0,1 mol of Cu was
observed traces of the second phase of ZnO. The FTIR spectra of the samples show two
absorption bands characteristic of OH group stretching band corresponding to stretching
and NO resulting from nitrate. The synthesized samples showed a high amount of
surface area, therefore nano-particle size. The morphology of ferrite samples doped with
and without calcination resulted in the appearance of irregular clumps and not dense.
The EDS mapping showed a good chemical homogeneity of constituent elements
characteristic of Ni-Zn ferrite with both dopants. The total mass loss by TGA and DTA
results was lower for the systems doped and annealed with 0,3 mol of Al3+ and 0,1 mol
of Cu2+. The Ni-Zn ferrite doped with 0,3 mol of Al3+ and 0,1 mol of Cu2+ showed
superparamagnetic behavior and after calcination, showed the formation of a material
with soft magnetic behavior (magnetization and demagnetization easy). The calcined
samples are promising soft magnetic devices and absorbers of electromagnetic
radiation, and the non-calcined for other applications such as catalysis, sensors and drug
carriers.