Investigation on Complex Permittivity and Permeability of La1-xSrxMnO3 Oxides

La 1-xSrxMnO3（x=0, 0.2, 0.4, 0.6） oxides were prepared through sol-gel method with even crystalline size 70 nm, complex permittivity and permeability behavior dependence on Sr contents in the range of 50～1800 MHz were discussed. When x=0, for LaMnO3 oxide, the complex permeability keeps a constant number, μ′r0.8, μ″r1.0 in the frequency range of 50～1800 MHz; the complex permittivity decreases as frequency increases, the ε′r decreases from 33 to 19 and the ε″r decreases from 65 to 5. However, when the specimen doped with Sr, it exhibits a relaxation character from the frequency spectrum curves of the complex permittivity and permeability. Moreover, the resonance frequency fr of the complex permeability decreases from 1420 to 809 MHz with Sr content increasing from 0.2 to 0.6, and the fr of the complex permittivity increases from 231 to 580 MHz as Sr content increases from 0.2 to 0.6. Furthermore, the mechanism of the AC magnetization and AC electric polarization were discussed.