TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO...TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 ℃ are of pure anatase and rutile, respectively. The scanning electron microscope (SEM) observations reveal that the crystal grain size increases with the annealing temperature, and the high resolution transmission electron microscopy (HRTEM) investigations further indicate that the samples are well crystallized, confirming that Mn has doped into the TiO2 crystal lattice effectively. The room temperature ferromagnetism, which could be explained within the scope of the bound magnetic polaron (BMP) theory, is detected in the Mn-TiO2 samples with Mn concentration of 2 at%, and the magnetization of the powders annealed at 500 ℃ is stronger than that of the sample treated at 800 ℃. The UV-VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping.展开更多
Mn-doped ZnO samples,Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05;mole fraction),were successfully synthesized by sonochemical method.The undoped and Mn-doped Zn O samples were characterized by X-ray diffraction(XRD),scanni...Mn-doped ZnO samples,Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05;mole fraction),were successfully synthesized by sonochemical method.The undoped and Mn-doped Zn O samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and Raman spectroscopy.XRD patterns of all products are identified to hexagonal wurtzite Zn O structure and their three main peaks shift toward lower diffraction angles due to the incorporation of Mn^(2+)into Zn O crystal lattice.The morphologies of Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05)were examined by SEM and TEM.The undoped Zn O sample shows large-scale uniform microflowers which are broken into nanorods and nanoparticles by Mn dopant.Their magnetic properties were investigated by a vibrating sample magnetometer at room temperature.The magnetization-applied field behavior of undoped Zn O defines its weak ferromagnetic behavior.The 3 mol%Mn-doped Zn O shows the highest saturation magnetization of 51.73910^(-3)m A·m^(2)·g^(-1),and the 5 mol%Mn-doped Zn O has suppressed ferromagnetic property due to the formation of Mn clusters inside.展开更多
基金Project supported by the Innovation Foundation of BUAA for PhD Graduates (Grant No. 292122)Equipment Research Foundation of China
文摘TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 ℃ are of pure anatase and rutile, respectively. The scanning electron microscope (SEM) observations reveal that the crystal grain size increases with the annealing temperature, and the high resolution transmission electron microscopy (HRTEM) investigations further indicate that the samples are well crystallized, confirming that Mn has doped into the TiO2 crystal lattice effectively. The room temperature ferromagnetism, which could be explained within the scope of the bound magnetic polaron (BMP) theory, is detected in the Mn-TiO2 samples with Mn concentration of 2 at%, and the magnetization of the powders annealed at 500 ℃ is stronger than that of the sample treated at 800 ℃. The UV-VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping.
基金financially supported by the National Research University(NRU)Project for Chiang Mai UniversityBansomdejchaopraya Rajabhat University(BSRU)Research Fund。
文摘Mn-doped ZnO samples,Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05;mole fraction),were successfully synthesized by sonochemical method.The undoped and Mn-doped Zn O samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and Raman spectroscopy.XRD patterns of all products are identified to hexagonal wurtzite Zn O structure and their three main peaks shift toward lower diffraction angles due to the incorporation of Mn^(2+)into Zn O crystal lattice.The morphologies of Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05)were examined by SEM and TEM.The undoped Zn O sample shows large-scale uniform microflowers which are broken into nanorods and nanoparticles by Mn dopant.Their magnetic properties were investigated by a vibrating sample magnetometer at room temperature.The magnetization-applied field behavior of undoped Zn O defines its weak ferromagnetic behavior.The 3 mol%Mn-doped Zn O shows the highest saturation magnetization of 51.73910^(-3)m A·m^(2)·g^(-1),and the 5 mol%Mn-doped Zn O has suppressed ferromagnetic property due to the formation of Mn clusters inside.