Negative permittivity and left-handed behavior of doped manganites in millimeter waveband

The effective plasma frequency of strontium-doped lanthanum manganite was determined basing on its double negative properties. The zone of high transmission (double negative zone) for spatially partitioned layered manganite specimen, immersed into dielectric matrix, was studied experimentally in millimeter waveband. It turns out that frequency dependence of manganite permittivity is well described by Drude formula, which includes only one parameter-the effective plasma frequency. Additionally, the negativity of the refraction index has been directly proved in experiments studying electromagnetic waves refraction in manganite prism. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3491155]