A series of Cu-substituted Ni_(0.5-x)Cu_xZn_(0.5)Fe_2O_4(x=0.12,0.16,0.20,0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the str...A series of Cu-substituted Ni_(0.5-x)Cu_xZn_(0.5)Fe_2O_4(x=0.12,0.16,0.20,0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the structure and dielectric properties.XRD patterns demonstrate that all the samples are crystallized in single-phase cubic spinel structure and the lattice constant increases with increasing Cu content.White grains observed by SEM are Cu-rich phase.The dielectric constant versus frequency curve displays a normal dielectric behavior of spinel ferrites.While the frequency dependence of dielectric loss tangent is found to be abnormal,exhibiting a peak at certain frequency for all Cu-substituted Ni-Zn ferrites.A maximum of the resistivity is observed at x=0.2 due to the decrease of hopping electrons between Fe^(2+) and Fe^(3+) in per unit volume,which is in contrast with the Cu content dependence of dielectric constant and dielectric loss.展开更多
报道了利用100Kev高剂量N^+在不同的温度条件下注入C膜合成新型超硬材料β-C_3N_4的新结果.对这种新材料进行了X射线光电子能谱,Fourier变换红外光谱、Raman光谱、剖面透射电子显微镜、Rutherford背散射谱、X射线衍射及Vickers显微硬度...报道了利用100Kev高剂量N^+在不同的温度条件下注入C膜合成新型超硬材料β-C_3N_4的新结果.对这种新材料进行了X射线光电子能谱,Fourier变换红外光谱、Raman光谱、剖面透射电子显微镜、Rutherford背散射谱、X射线衍射及Vickers显微硬度等测量.结果表明利用100Kev高剂量N^+注入C膜成功地合成了埋层氮化碳CN_(?)膜中C≡N共价键的形成导致膜的硬度明显提高.最后利用Implantation of Reactive Ions into Silicon (IRIS)计算程序模拟了相同条件的N^+注入C膜合成埋层β-C_3N_4的形成过程,结果与实验符合较好.展开更多
基金Project(M26012)supported by the Foundation of National Laboratory of Solid State Microstructures,China
文摘A series of Cu-substituted Ni_(0.5-x)Cu_xZn_(0.5)Fe_2O_4(x=0.12,0.16,0.20,0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the structure and dielectric properties.XRD patterns demonstrate that all the samples are crystallized in single-phase cubic spinel structure and the lattice constant increases with increasing Cu content.White grains observed by SEM are Cu-rich phase.The dielectric constant versus frequency curve displays a normal dielectric behavior of spinel ferrites.While the frequency dependence of dielectric loss tangent is found to be abnormal,exhibiting a peak at certain frequency for all Cu-substituted Ni-Zn ferrites.A maximum of the resistivity is observed at x=0.2 due to the decrease of hopping electrons between Fe^(2+) and Fe^(3+) in per unit volume,which is in contrast with the Cu content dependence of dielectric constant and dielectric loss.
基金National Nature Science Foundation(No.60676055)National Key Project for Basic Research(No.2005CB623605)Nature Science Foundation and Educational Office Foundation of Fujian Province(No.E0320002 and JB08062)
文摘报道了利用100Kev高剂量N^+在不同的温度条件下注入C膜合成新型超硬材料β-C_3N_4的新结果.对这种新材料进行了X射线光电子能谱,Fourier变换红外光谱、Raman光谱、剖面透射电子显微镜、Rutherford背散射谱、X射线衍射及Vickers显微硬度等测量.结果表明利用100Kev高剂量N^+注入C膜成功地合成了埋层氮化碳CN_(?)膜中C≡N共价键的形成导致膜的硬度明显提高.最后利用Implantation of Reactive Ions into Silicon (IRIS)计算程序模拟了相同条件的N^+注入C膜合成埋层β-C_3N_4的形成过程,结果与实验符合较好.
