This paper addresses the manipulation of structural,morphology,optical and magnetic properties of LiCo0.25Zn0.25Fe2 O4 ferrite via incorporation of different proportions of La^3+at the expense of iron ions using a sol...This paper addresses the manipulation of structural,morphology,optical and magnetic properties of LiCo0.25Zn0.25Fe2 O4 ferrite via incorporation of different proportions of La^3+at the expense of iron ions using a sol-gel method.The samples were characterized using the X-ray diffraction technique(XRD),Fourier transform infrared(FT-IR)spectroscopy,the energy dispersive X-ray spectra(EDX),inductively coupled plasma optical emission spectroscopy(ICP-OES),high resolution scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET)surface area analysis,ultraviolet-diffuse reflectance spectroscopy(UV-DRS),and vibrating sample magnetometer(VSM)technique.The Rietveld refinements of the samples indicate that at higher concentrations of La^3+,nanostructures with dual phase,i.e.cubic spinel and orthorhombic LaFeO3 perovskite with space group(Pbnm)appear.Optical studies show that the energy band gap(Eg)of the bare LiCo0.25Zn0.25Fe2 O4 ferrite sample(2.18 eV)reaches up to 2.47 eV at x=0.06 and above this concentration,it drops sharply to 2.00 eV.Although the saturation magnetization and the coercivity of LiCo0.25Zn0.25LaxFe2-xO4 are lower than that of LiCo0.25Zn0.25Fe2 O4 NPs.Overall,the superparamagnetic nature and low values of saturation magnetization and coercivity of LiCo0.25Zn0.25LaxFe2-xO4 NPs are suitable to be applied in transformers core.展开更多
The properties of γ-ray-reduced graphene oxide samples(GRGOs)were compared with those of hydrazine hydrate-reduced graphene oxide(HRGO).Fourier transform infrared spectroscopy,X-ray diffractometry,Raman spectroscopy,...The properties of γ-ray-reduced graphene oxide samples(GRGOs)were compared with those of hydrazine hydrate-reduced graphene oxide(HRGO).Fourier transform infrared spectroscopy,X-ray diffractometry,Raman spectroscopy,Brunauer-Emmett-Teller surface area analysis,thermogravimetric analysis,electrometry,and cyclic voltammetry were carried out to verify the reduction process,structural changes,and defects of the samples,as well as to measure their thermal,electrical,and electrochemical properties.Irradiation with γ-rays distorted the structure of GRGOs and generated massive defects through the extensive formation of new smaller sp^(2)-hybridized domains compared with those of HRGO.The thermal stability of GRGOs was higher than that of HRGO,indicating the highly efficient removal of thermally-labile oxygen species by γ-rays.RRGO prepared at 80 kGy showed a pseudocapacitive behavior comparable with the electrical double-layer capacitance behavior of HRGO.Interestingly,the specific capacitance of GRGO was enhanced by nearly three times compared with that of HRGO.These results reflect the advantages of radiation reduction in energy storage applications.展开更多
基金the Materials Science Unit,Radiation Physics Department,National Center for Radiation Research and Technology,Egypt,for financing and supporting this study under the project Nanostructured Magnetic Materials。
文摘This paper addresses the manipulation of structural,morphology,optical and magnetic properties of LiCo0.25Zn0.25Fe2 O4 ferrite via incorporation of different proportions of La^3+at the expense of iron ions using a sol-gel method.The samples were characterized using the X-ray diffraction technique(XRD),Fourier transform infrared(FT-IR)spectroscopy,the energy dispersive X-ray spectra(EDX),inductively coupled plasma optical emission spectroscopy(ICP-OES),high resolution scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET)surface area analysis,ultraviolet-diffuse reflectance spectroscopy(UV-DRS),and vibrating sample magnetometer(VSM)technique.The Rietveld refinements of the samples indicate that at higher concentrations of La^3+,nanostructures with dual phase,i.e.cubic spinel and orthorhombic LaFeO3 perovskite with space group(Pbnm)appear.Optical studies show that the energy band gap(Eg)of the bare LiCo0.25Zn0.25Fe2 O4 ferrite sample(2.18 eV)reaches up to 2.47 eV at x=0.06 and above this concentration,it drops sharply to 2.00 eV.Although the saturation magnetization and the coercivity of LiCo0.25Zn0.25LaxFe2-xO4 are lower than that of LiCo0.25Zn0.25Fe2 O4 NPs.Overall,the superparamagnetic nature and low values of saturation magnetization and coercivity of LiCo0.25Zn0.25LaxFe2-xO4 NPs are suitable to be applied in transformers core.
基金financially supported by the International Atomic Energy Agency in the framework of the Coordinated Research Project F22070.
文摘The properties of γ-ray-reduced graphene oxide samples(GRGOs)were compared with those of hydrazine hydrate-reduced graphene oxide(HRGO).Fourier transform infrared spectroscopy,X-ray diffractometry,Raman spectroscopy,Brunauer-Emmett-Teller surface area analysis,thermogravimetric analysis,electrometry,and cyclic voltammetry were carried out to verify the reduction process,structural changes,and defects of the samples,as well as to measure their thermal,electrical,and electrochemical properties.Irradiation with γ-rays distorted the structure of GRGOs and generated massive defects through the extensive formation of new smaller sp^(2)-hybridized domains compared with those of HRGO.The thermal stability of GRGOs was higher than that of HRGO,indicating the highly efficient removal of thermally-labile oxygen species by γ-rays.RRGO prepared at 80 kGy showed a pseudocapacitive behavior comparable with the electrical double-layer capacitance behavior of HRGO.Interestingly,the specific capacitance of GRGO was enhanced by nearly three times compared with that of HRGO.These results reflect the advantages of radiation reduction in energy storage applications.
