Coexistence of localized and itinerant carriers near T-C in calcium-doped manganites | |
Article | |
关键词: COLOSSAL-MAGNETORESISTANCE; FERROMAGNETIC TRANSITION; POLARON CROSSOVER; PEROVSKITE; LA1-XCAXMNO3; RESISTIVITY; TRANSPORT; LA0.67CA0.33MNO3; LA2/3CA1/3MNO3; LA1-XSRXMNO3; | |
DOI : 10.1103/PhysRevB.60.1028 | |
来源: SCIE |
【 摘 要 】
We explore the possibility that polaronic distortions in the paramagnetic phase of La0.67Ca0.33MnO3 manganites persist in the ferromagnetic phase by considering the observed electrical resistivity to arise from coexisting field- and temperature-dependent polaronic and band-electron fractions. We use an effective medium approach to compute the total resistivity of the two-component system, and find that a limit with low percolation threshold explains the data rather well. To test the validity of this model, we apply it to the thermoelectric coefficient. We propose a plausible mean-field model that reproduces the essential features of a microscopic model and provides a comparison with the experimental mixing fraction, as well as the magnetization and magnetic susceptibility.
【 授权许可】
Free