Precursive iron films with different grain sizes were prepared by magnetron sputtering on substrates heated at different temperatures. The iron films were sulfurized at 673 K for 20 h to form pyrite films. The structu...Precursive iron films with different grain sizes were prepared by magnetron sputtering on substrates heated at different temperatures. The iron films were sulfurized at 673 K for 20 h to form pyrite films. The structural and electrical characters were determined. High substrate temperatures produce large crystallites in the precursive iron films. The pyrite films are composed of a surface layer with coarse columnar grains and a bottom layer with fine equiaxed grains. With the increase of iron grain scale, the carrier concentration decreases and the carrier mobility increases. The electrical resistivity of the pyrite films increases to a maximum in the precursive iron films with increasing the grain size to about 3g nm. Sufficient formation and growth of iron grains result in improved crystallinity and high continuity of the pyrite films. The crystal defect density, transformation stress level and atom diffusion behavior are responsible for the characteristics of the electrical properties dependent on the crystallinity and continuity of the pyrite films or the crystallizing status of the precursive iron films.展开更多
Fe2O3/SiO2 nano-composite films were prepared by sol-gel technique combining heat treatment in the range of 100-900 ℃. The particle size was observed by FE-SEM. Optical properties of the films were investigated by UV...Fe2O3/SiO2 nano-composite films were prepared by sol-gel technique combining heat treatment in the range of 100-900 ℃. The particle size was observed by FE-SEM. Optical properties of the films were investigated by UV-visible spectra. Structural and magnetic characteristics were investigated through FT-IR and VSM. The transparency of the Fe2O3/SiO2 nano-composite films decreased with the content of the Fe2O3. Water and organic solvent in the films were evaporated with heat treatment, so the transparency of the films was enhanced under high temperature. It is also found that the saturation magnetization （Ms） of the films increases with the temperature. As the content of the Fe2O3 increases, when the content of the Fe2O3 is around 30wt%, the Ms of the films has a maximum value.展开更多
Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples...Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples calcined at and above 600 ℃ have a single-phase spinel structure and the average grain size of the sample calcined at 600 ℃ is about 20 nm. The initial permeability μi, saturation magnetization M and coercivity H of the samples increase with the increasing calcination temperature. The sample calcined at 600 ℃ exhibits an excellent soft magnetic performance, which has μi=33.97 （10 MHz）, Hc=15.62 Oe and Ms=228.877 emu/cm^3. Low-temperature annealing can enhance the magnetic properties of the samples. The work shows that using the sol-gel method in conjunction with RTA is a promising way to fabricate integrated thin-film devices.展开更多
基金supported by the National NaturalScience Foundation of China (Grant No. 50871103).
文摘Precursive iron films with different grain sizes were prepared by magnetron sputtering on substrates heated at different temperatures. The iron films were sulfurized at 673 K for 20 h to form pyrite films. The structural and electrical characters were determined. High substrate temperatures produce large crystallites in the precursive iron films. The pyrite films are composed of a surface layer with coarse columnar grains and a bottom layer with fine equiaxed grains. With the increase of iron grain scale, the carrier concentration decreases and the carrier mobility increases. The electrical resistivity of the pyrite films increases to a maximum in the precursive iron films with increasing the grain size to about 3g nm. Sufficient formation and growth of iron grains result in improved crystallinity and high continuity of the pyrite films. The crystal defect density, transformation stress level and atom diffusion behavior are responsible for the characteristics of the electrical properties dependent on the crystallinity and continuity of the pyrite films or the crystallizing status of the precursive iron films.
基金Funded by the Innovative Program of Shanghai Municipal Education Commission (No.08YZ97)the National Natural Science Foundation of China (No.10704048)
文摘Fe2O3/SiO2 nano-composite films were prepared by sol-gel technique combining heat treatment in the range of 100-900 ℃. The particle size was observed by FE-SEM. Optical properties of the films were investigated by UV-visible spectra. Structural and magnetic characteristics were investigated through FT-IR and VSM. The transparency of the Fe2O3/SiO2 nano-composite films decreased with the content of the Fe2O3. Water and organic solvent in the films were evaporated with heat treatment, so the transparency of the films was enhanced under high temperature. It is also found that the saturation magnetization （Ms） of the films increases with the temperature. As the content of the Fe2O3 increases, when the content of the Fe2O3 is around 30wt%, the Ms of the films has a maximum value.
基金the National Natural Science Foundation of China (No. 90607021).
文摘Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples calcined at and above 600 ℃ have a single-phase spinel structure and the average grain size of the sample calcined at 600 ℃ is about 20 nm. The initial permeability μi, saturation magnetization M and coercivity H of the samples increase with the increasing calcination temperature. The sample calcined at 600 ℃ exhibits an excellent soft magnetic performance, which has μi=33.97 （10 MHz）, Hc=15.62 Oe and Ms=228.877 emu/cm^3. Low-temperature annealing can enhance the magnetic properties of the samples. The work shows that using the sol-gel method in conjunction with RTA is a promising way to fabricate integrated thin-film devices.
