Feo.eCoo.^seHfTBsCu! nanocrystalline alloy obtained in isothermal annealing process from amorphous precursor was investigated as candidate of soft magnetic materials for high temperature applications. Co substitution ...Feo.eCoo.^seHfTBsCu! nanocrystalline alloy obtained in isothermal annealing process from amorphous precursor was investigated as candidate of soft magnetic materials for high temperature applications. Co substitution for Fe can enhance the curie temperature of amorphous alloy (Tc = 630 °C) and improve the magnetization of nanocrystalline alloy at high temperature ( = 1.56T at 550 °C). After annealing amorphous precursor at 550 °C for 1 hour, the optimum nanocrystalline alloy can be obtained which shows the local minimum coercivity ( = 16 A/m). The coercivity increases with the increase of annealing temperature corresponding to the formation of ferromagnetic phase in the secondary crystallization. Furthermore, additions of Hf and B elements reduce the melting temperature of the alloy studied comparing with the Fe-Co binary alloy.展开更多
Amorphous La2Hf2O7 thin films were deposited on Si（100） substrate by pulsed laser deposition （PLD） method under different con-ditions. The interfacial states of the La2Hf2O7/Si films were studied by synchrotron X-...Amorphous La2Hf2O7 thin films were deposited on Si（100） substrate by pulsed laser deposition （PLD） method under different con-ditions. The interfacial states of the La2Hf2O7/Si films were studied by synchrotron X-ray reflectivity （XRR） and X-ray photoelectron spec-troscopy （XPS）. When grown under vacuum condition, silicate, silicide and few SiOx were formed in the interface layer. However, the Hf-silicide formation could be effectively eliminated by the ambient oxygen pressure during film growth. The result revealed that the La2Hf2O7/Si interlayer was intimately related with growth condition. Insufficient supply of oxygen would cause Hf-silicide formation at the interface and it could be most effectively controlled by the ambient oxygen pressure during film growth.展开更多
Abstract： Amorphous LazHf2O7 films were grown on Si（100） by pulsed laser deposition method. The valence and conduction band offsets between amorphous La2Hf2O7 film and silicon were determined by using synchrotron r...Abstract： Amorphous LazHf2O7 films were grown on Si（100） by pulsed laser deposition method. The valence and conduction band offsets between amorphous La2Hf2O7 film and silicon were determined by using synchrotron radiation photoemission spectroscopy. The energy band gap of amorphous La2Hf2O7 film was measured from the energy-loss spectra of O ls photoelectrons. The band gap of amorphous LazHf2O7 film was determined to be 5.4±0.2 eV. The valence and the conduction-band offsets of amorphous La2Hf2O7 film to Si were obtained to be 2.7±0.2 and 1.6±0.2 eV, respectively. These results indieated that the amorphous La2Hf2O7 film could be one promising candidate for high-k gate dielectrics.展开更多
基金supported by the 5^(th)framework Program of European Community,research project“Soft Magnetic.Nanomaterials for High Temperature and High Frequency Functional Application in Power Electronics",contract No.GSRD-CT-2001-03009.the key project of National Natural Science Foundation of China(50235030).
文摘Feo.eCoo.^seHfTBsCu! nanocrystalline alloy obtained in isothermal annealing process from amorphous precursor was investigated as candidate of soft magnetic materials for high temperature applications. Co substitution for Fe can enhance the curie temperature of amorphous alloy (Tc = 630 °C) and improve the magnetization of nanocrystalline alloy at high temperature ( = 1.56T at 550 °C). After annealing amorphous precursor at 550 °C for 1 hour, the optimum nanocrystalline alloy can be obtained which shows the local minimum coercivity ( = 16 A/m). The coercivity increases with the increase of annealing temperature corresponding to the formation of ferromagnetic phase in the secondary crystallization. Furthermore, additions of Hf and B elements reduce the melting temperature of the alloy studied comparing with the Fe-Co binary alloy.
基金Projects supported by the National Natural Science Foundation of China (10974191)the School Doctorial Foundation of Zhengzhou University of Light Industry (2010BSJJ028)
文摘Amorphous La2Hf2O7 thin films were deposited on Si（100） substrate by pulsed laser deposition （PLD） method under different con-ditions. The interfacial states of the La2Hf2O7/Si films were studied by synchrotron X-ray reflectivity （XRR） and X-ray photoelectron spec-troscopy （XPS）. When grown under vacuum condition, silicate, silicide and few SiOx were formed in the interface layer. However, the Hf-silicide formation could be effectively eliminated by the ambient oxygen pressure during film growth. The result revealed that the La2Hf2O7/Si interlayer was intimately related with growth condition. Insufficient supply of oxygen would cause Hf-silicide formation at the interface and it could be most effectively controlled by the ambient oxygen pressure during film growth.
基金Projects supported by National Natural Science Foundation of China(10974191)Doctorial Foundation of Zhengzhou University of LightIndustry(2010BSJJ028)
文摘Abstract： Amorphous LazHf2O7 films were grown on Si（100） by pulsed laser deposition method. The valence and conduction band offsets between amorphous La2Hf2O7 film and silicon were determined by using synchrotron radiation photoemission spectroscopy. The energy band gap of amorphous La2Hf2O7 film was measured from the energy-loss spectra of O ls photoelectrons. The band gap of amorphous LazHf2O7 film was determined to be 5.4±0.2 eV. The valence and the conduction-band offsets of amorphous La2Hf2O7 film to Si were obtained to be 2.7±0.2 and 1.6±0.2 eV, respectively. These results indieated that the amorphous La2Hf2O7 film could be one promising candidate for high-k gate dielectrics.
