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. Epita xial thin films of perovskite manganites La1-xBxMnO3-delta (B=Ca,Sr) w ere prepared on SrTiO3 (100) substrates using on- and off-axis pulsed laser deposition (PLD) techniques. X-ray diffraction, resistance and m agnetoresistance measurements, as well as,high-resolution transmission electron microscopy (HRTEM) investigations were carried out. HRTEM ob servations reveal epitaxial growth for the first few layers of all pre pared samples. Thicker on-axis prepared films grow with a large number of defects, whereas off-axis prepared samples grow in a columnar stru cture. Since the magnetic properties in systems with double-exchange i nteraction are very sensitive to the local structure it has great infl uence on the electronic properties. (C) 1997 American Institute of Phy sics.