We report systematic in-plane magnetoresistance measurements on the electron-doped cuprate La2-x,.CexCuO4±δ thin films as a function of Ce doping and oxygen content in the magnetic field up to 14 T. A crossover ...We report systematic in-plane magnetoresistance measurements on the electron-doped cuprate La2-x,.CexCuO4±δ thin films as a function of Ce doping and oxygen content in the magnetic field up to 14 T. A crossover from negative to positive magnetoresistance occurs between the doping level x = 0.07 and 0.08. Above x = 0.08, the positive magnetoresistance effect appears, and is almost indiscernible at x = 0.15. By tuning the oxygen content, the as-grown samples show negative magnetoresistance effect, whereas the optimally annealed ones display positive magnetoresistance effect at the doping level x = 0.15. Intriguingly, a linear-field dependence of in-plane magnetoresistanee is observed at the underdoping level x = 0.06, the optimal doping level x = 0. i and slightly overdoping level x = 0.11. These anomalies of in-plane magnetoresistance may be related to the intrinsic inhomogeneity in the cuprates, which is discussed in the framework of network model.展开更多
In this paper,we investigate the possibility of using the heterogeneous materials,with cuboid metallic inclusions inside a dielectric substrate(host)to control the effective permittivity.We find that in the gigahertz ...In this paper,we investigate the possibility of using the heterogeneous materials,with cuboid metallic inclusions inside a dielectric substrate(host)to control the effective permittivity.We find that in the gigahertz range,such a material demonstrates a significantly larger permittivity compared to the pure dielectric substrate.Three principal orientations of microscale cuboid inclusions have been taken into account in this study.The highest permittivity is observed when the orientation provides the largest polarization(electric dipole moment).The detrimental side effect of the metallic inclusion,which leads to the decrease of the effective magnetic permeability,can be suppressed by the proper choice of shape and orientation of the inclusions.This choice can in fact reduce the induced current and hence maximize the permeability.The dissipative losses are shown to be negligible in the relevant range of frequencies and cuboid dimensions.展开更多
基金supported by the National Key Basic Research Program of China (Grant Nos. 2015CB921000, and 2016YFA0300301)the National Natural Science Foundation of China (Grant Nos. 11674374, and 11474338)the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Grant No. QYZDB-SSW-SLH008)
文摘We report systematic in-plane magnetoresistance measurements on the electron-doped cuprate La2-x,.CexCuO4±δ thin films as a function of Ce doping and oxygen content in the magnetic field up to 14 T. A crossover from negative to positive magnetoresistance occurs between the doping level x = 0.07 and 0.08. Above x = 0.08, the positive magnetoresistance effect appears, and is almost indiscernible at x = 0.15. By tuning the oxygen content, the as-grown samples show negative magnetoresistance effect, whereas the optimally annealed ones display positive magnetoresistance effect at the doping level x = 0.15. Intriguingly, a linear-field dependence of in-plane magnetoresistanee is observed at the underdoping level x = 0.06, the optimal doping level x = 0. i and slightly overdoping level x = 0.11. These anomalies of in-plane magnetoresistance may be related to the intrinsic inhomogeneity in the cuprates, which is discussed in the framework of network model.
基金The project was funded by the EPSRC Grant(EP/101490X/1)on synthetic materials and metamaterials studies.
文摘In this paper,we investigate the possibility of using the heterogeneous materials,with cuboid metallic inclusions inside a dielectric substrate(host)to control the effective permittivity.We find that in the gigahertz range,such a material demonstrates a significantly larger permittivity compared to the pure dielectric substrate.Three principal orientations of microscale cuboid inclusions have been taken into account in this study.The highest permittivity is observed when the orientation provides the largest polarization(electric dipole moment).The detrimental side effect of the metallic inclusion,which leads to the decrease of the effective magnetic permeability,can be suppressed by the proper choice of shape and orientation of the inclusions.This choice can in fact reduce the induced current and hence maximize the permeability.The dissipative losses are shown to be negligible in the relevant range of frequencies and cuboid dimensions.
