Detection of phase separation and nano-droplet states in La_033Pr_034Ca_033MnO_3 nanowires via near-infrared reflection experiments

Abstract

We present an optical investigation on La0.33Pr0.34Ca0.33MnO3 (LPCMO) nanowires by using standard near-infrared (NIR) reflection experiments. It is found that the samples can respond strongly to the NIR radiation so that the temperature dependence of the reflectivity can be measured accordingly. Interestingly, the temperature induced phase separation and nano-droplet states in the nanowire samples with different diameters can be identified and observed optically without making ohmic contact electrodes on the samples. The onset temperature of the nano-droplet state measured optically is in line with that obtained from previous transport measurements. Importantly, via examining the dependence of the NIR reflectivity upon radiation wavelength, we find that the electronic localization effect exists in the LPCMO nanowires in both electronic states. Such information cannot be directly obtained from electric transport and magneto-transport experiments. The interesting and important experimental findings from this study demonstrate that the simple and contactless NIR reflection measurements can be employed to conveniently study and characterize the basic physical properties of perovskite manganites based nanostructure systems.