STRUCTURAL EVOLUTION OF HIGH-ENERGY BALL-MILLED NANOCRYSTALLINE La_(0.67)Ca_(0.33)MnO_(3-L) USING EXTENDED X-RAY ABSORPTION FINE STRUCTURE

摘要

Doped-La manganites of the general formula La_xA_(1-x)MnO_(3-L) (where A is typically divalent cations e.g. Ca, Sr, Y, Ba) have received considerable interest due to their unusual magnetic and electronic properties, most notably, the large change in magnetoresistance that accompanies an insulator-to-metal transition known as colossal magnetoresistance. We have prepared nanostructured compounds of La_(0.67)Ca_(0.33)MnO_(3-L) using high-energy ball milling. The structural evolution of these compounds has been studied as a function of milling time using extended x-ray absorption fine structure and x-ray diffraction. This information is correlated with magnetism and transport properties.