Crystal structure, electrical properties and Raman spectra of BaBi1-xPbxO3 are reported. The result of x-ray diffraction shows that the specimen is pure, and the lattice parameters decrease continuously in the semicon...Crystal structure, electrical properties and Raman spectra of BaBi1-xPbxO3 are reported. The result of x-ray diffraction shows that the specimen is pure, and the lattice parameters decrease continuously in the semiconducting range, whereas it vibrates similarly to a sine wave in the superconducting range, which is ascribed to the existence of oxygen vacancies and the function of breathing modes of Bi（Pb）O6. The temperature dependence of resistivity indicates that the electrical property of the samples is connected sensitively with the crystal structures. Raman spectra show that the specimen becomes disorder when x increases, and the critical temperature To depends not only on the deformation potential of the soft A19 mode derived from the Bi（Pb）O6 rigid rotation, but also on the energy shift of the mode.展开更多
The normal-state charge transport of high-Tc cuprates has been one of the focuses in understanding the high-Tc mechanism.We recently studied the temperature-dependent ab-plane resistivity of Bi2Sr2CuOy crystals,and fo...The normal-state charge transport of high-Tc cuprates has been one of the focuses in understanding the high-Tc mechanism.We recently studied the temperature-dependent ab-plane resistivity of Bi2Sr2CuOy crystals,and found that many of the as-grown crystals exhibited metallic conduction at high temperature,but localized behavior at low temperature.The magnetoresistance measurement has been performed on the crystals showing strong-localization behavior.It is found that in the low temperature regime the samples show positive magnetoresistance at low field,but negative at high field.The magnetic field corresponding to the maximum positive magnetoresistance shifts to the direction of low field with the increase of the temperature.However,in the high temperature regime,only the negative magnetoresistance is observed no matter how the field is.With further increase of the temperature the magnetoresistance effect becomes less prominent.By comparison of the magnetoresistance in longitudinal direction with that展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10104013 and 50421201, and the National Basic Research Programme of China under Grant No 2006CB601003.
文摘Crystal structure, electrical properties and Raman spectra of BaBi1-xPbxO3 are reported. The result of x-ray diffraction shows that the specimen is pure, and the lattice parameters decrease continuously in the semiconducting range, whereas it vibrates similarly to a sine wave in the superconducting range, which is ascribed to the existence of oxygen vacancies and the function of breathing modes of Bi（Pb）O6. The temperature dependence of resistivity indicates that the electrical property of the samples is connected sensitively with the crystal structures. Raman spectra show that the specimen becomes disorder when x increases, and the critical temperature To depends not only on the deformation potential of the soft A19 mode derived from the Bi（Pb）O6 rigid rotation, but also on the energy shift of the mode.
基金Project supported by the National Center of Research and Development on Superconductivity.
文摘The normal-state charge transport of high-Tc cuprates has been one of the focuses in understanding the high-Tc mechanism.We recently studied the temperature-dependent ab-plane resistivity of Bi2Sr2CuOy crystals,and found that many of the as-grown crystals exhibited metallic conduction at high temperature,but localized behavior at low temperature.The magnetoresistance measurement has been performed on the crystals showing strong-localization behavior.It is found that in the low temperature regime the samples show positive magnetoresistance at low field,but negative at high field.The magnetic field corresponding to the maximum positive magnetoresistance shifts to the direction of low field with the increase of the temperature.However,in the high temperature regime,only the negative magnetoresistance is observed no matter how the field is.With further increase of the temperature the magnetoresistance effect becomes less prominent.By comparison of the magnetoresistance in longitudinal direction with that
