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−δ (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.