Structure and magnetoresistive properties in La-manganite thin films

This study investigates the structure of perovskite thin films and its influence on their colossal magnetoresistance (CMR) properties. Epitaxial thin films of perovskite manganites La1-xBxMnO3-delta (B=Ca,Sr) were prepared on SrTiO3 (100) substrates using on- and off-axis pulsed laser deposition (PLD) techniques. X-ray diffraction, resistance and magnetoresistance measurements, as well as,high-resolution transmission electron microscopy (HRTEM) investigations were carried out. HRTEM observations reveal epitaxial growth for the first few layers of all prepared samples. Thicker on-axis prepared films grow with a large number of defects, whereas off-axis prepared samples grow in a columnar structure. Since the magnetic properties in systems with double-exchange interaction are very sensitive to the local structure it has great influence on the electronic properties. (C) 1997 American Institute of Physics.